Device registration in a hierarchical monitor service

ABSTRACT

Monitor services deployable on device networks may be implemented using a modular approach, in which a core monitor service is mapped to one or more devices included in, or associated with, the device networks. Additional monitoring-related functionality may be provided to such devices using plug-ins, add-on services or service components, or other service modules, which interact with the core monitor service. The core monitor service(s) and any monitor service modules may be mapped, to specific ones of the devices, based on, for example, requirements of other services and/or relevant device metadata (e.g., capabilities) of the devices. In additional or alternative implementations, various protocols may be used to register new devices and deployed monitor service(s) with the distributed monitoring service(s) in a fast, secure, energy-efficient, and reliable manner, even as devices join or leave the device network(s).

TECHNICAL FIELD

This description relates to ubiquitous computing technologies.

BACKGROUND

Smart item technologies may include, for example, radio-frequencyidentification (RFID) systems, embedded systems, sensor motes, and/orsensor networks, and may be used, for example, to provide businesssoftware applications with fast access to real-world data. For example,smart item technologies may be used support the detection, reading, orwriting of RFID tags, as well as to support communication with, andcontrol of, wireless sensor networks and embedded systems. In manyinstances, smart items may include devices having local processingpower, memory, and/or communication capabilities, that are capable ofproviding data about the device and its properties, or information abouta current state or environment of the smart item devices. Accordingly,some such devices may be used in the execution of service components ofback-end or underlying business applications, and, in particular, may doso in a collaborative way, e.g., by forming mobile ad-hoc networks tocollect, process, or transmit business data.

Examples of smart item devices include an RFID tag, which may be passiveor active, and which may be attached to a real-world object and used toprovide product or handling information related to the object. Otherexamples of smart item devices includes various sensors, such as, forexample, environmental sensors (e.g., a temperature, humidity, orvibration sensor), which, as just referenced, may be capable ofcommunicating to form one or more sensor networks. These and other typesof smart item devices also may include embedded systems, which may refergenerally to any system in which a special-purpose processor and/orprogram is included, and/or in which the system is encapsulated in thedevice being controlled.

Through automatic real-time object tracking, smart item technology mayprovide businesses with accurate and timely data about businessoperations, and also may help streamline and automate the businessoperations. Accordingly, cost reductions and additional businessbenefits (e.g., increased asset visibility, improved responsiveness, andextended business opportunities) may be obtained.

SUMMARY

According to one general aspect, a method includes transmitting, from aregistering monitor service at a first tier of a hierarchical,multi-tier monitoring architecture for a device network, a solicitationmessage identifying both the registering monitor service, and aregistered monitor service associated with a second, higher tier of thehierarchical, multi-tier monitoring architecture. The method alsoincludes transmitting, from the registered monitor service, anadvertisement message indicating an identity and availability of theregistered monitoring service for registration, and transmitting, fromthe registering monitor service, a registration message includingregistration data associated with the registering monitor service. Themethod also includes registering the registering monitor service withinthe hierarchical, multi-tier monitoring architecture, based on theregistration data.

Implementations may include one or more of the following features. Forexample, the method may include transmitting, from the registeredmonitor service, a confirmation message confirming registration of theregistering monitor service.

In transmitting the solicitation message, the solicitation message maybe transmitted to the second, higher tier, after a previous transmittingto an intervening tier does not result in receiving the advertisementmessage. Transmitting the solicitation message also may includebroadcasting the solicitation message at a pre-determined time interval.

Transmitting the advertisement message may include transmitting theadvertisement message based on the solicitation message. Transmittingthe advertisement message may include transmitting the advertisementmessage based on a pre-determined time interval, and independently ofthe solicitation message.

Transmitting the registration message may include including, within theregistration data, device metadata within the registration message andassociated with a device on which the connecting service is deployed,and/or including, within the registration data, service metadata withinthe registration message and associated with a service deployed on thedevice. Transmitting the registration message also may includeincluding, within the registration data, sensor values obtained by asensor associated with the connecting service.

Transmitting the registration message may include re-transmitting theregistration message until the confirmation message is received or untila time-out condition is reached, and/or may include discarding, at theregistering monitor services, a further advertisement message receivedafter the registration message is transmitted. Additionally, oralternatively, transmitting the registration message may include storingthe registration data using at least one device associated with theregistered monitor service, and/or updating global monitor data for thehierarchical, multi-tiered monitor architecture, based on theregistration data, to reflect the registration of the registeringmonitor service with a global monitor service.

A core monitor service may be deployed onto the registering monitorservice, and device metadata associated with a device on which theregistering monitor service is deployed may be determined. At least onemonitor service module may be deployed onto the device, based on thedevice metadata. The solicitation message may be transmitted, theadvertisement message may be received, and/or the registration messagemay be transmitted, using the at least one monitor service module.

According to another general aspect, a system includes a monitor serviceconfigured to obtain and report monitor data regarding a device networkat a first level of a hierarchical, multi-tiered monitor service. Themonitor service includes a registration system configured to send asolicitation message from the monitor service, the solicitation messagespecifying, by tier, a registered monitor service at a higher-level tierof the hierarchical, multi-tiered monitor architecture, the registrationsystem being further configured to receive an advertisement message fromthe registered monitor service, determine that the registered monitorservice is a member of the specified tier based on the advertisementmessage, and send a registration message to the registered monitorservice.

Implementations may include one or more of the following features. Forexample, the registration system may be configured to receive aconfirmation message from the registered monitor service, in response tothe registration and confirming that the monitor service is registeredwith a global monitor service associated with the device network. Theregistration message may include registration data that is stored, atleast in part, using the global monitor service and any interveningmonitor service between the registering monitor service and the globalmonitor service.

According to another general aspect, a method includes receiving asolicitation message from a monitor service at a registered monitorservice of a hierarchical, multi-tiered monitor architecture for adevice network, determining that the monitor service is not registeredthrough the registered monitor service as a member of the hierarchical,multi-tiered monitor architecture, and determining an identification ofa tier specified in the solicitation message, the registered monitorservice being deployed on the tier. The method may include sending anadvertisement message to the monitor service, the advertisementspecifying the registered monitor service as being deployed on the tierand available for registration, receiving a registration message fromthe monitor service, and registering the monitor service within thehierarchical, multi-tiered monitor architecture, based on theregistration message.

Implementations may include one or more of the following features. Forexample, a confirmation message may be sent to the monitor service.Additionally, or alternatively, sending the advertisement message mayinclude sending the advertisement message in response to thesolicitation message. Registering the monitor service may includestoring, locally to the registered monitor service, registration datareceived from the monitor service as part of the registration message,and updating a memory of a higher-tier monitor service, above theregistered monitor service, based on the registration data.

The details of one or more implementations are set forth in theaccompanying drawings and the description below. Other features will beapparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of a system for monitoring smart items.

FIG. 2 is a block diagram illustrating an example deployment of thesystem of FIG. 1.

FIG. 3 is a block diagram illustrating a second example deployment ofthe system of FIG. 1

FIG. 4 is a block diagram of a smart items infrastructure forimplementing the systems of FIGS. 1, 2, and 3.

FIG. 5 is a timing diagram illustrating an example algorithm forgathering monitor data using the system of FIG. 1.

FIG. 6 is a block diagram of a modular monitor service that mayrepresent one or more of the monitor services 132 a-132 d of FIG. 1.

FIG. 7A is a flowchart illustrating an operation of the system of FIG. 1using the modular monitor service of FIGS. 1 and 6.

FIG. 7B is a flowchart illustrating additional example operations of thesystem of FIG. 1.

FIG. 8 is a block diagram of an example implementation of a core monitorservice of FIGS. 1 and 6.

FIG. 9 is a block diagram illustrating a system adaptor manager for usewith the modular monitor service of FIG. 6 and/or the implementation ofthe core monitor service illustrated in FIG. 8.

FIG. 10 is a block diagram of an example implementation of a systemadaptors of FIGS. 1, 6, and 9.

FIG. 11 is a block diagram of another example implementation of systemadaptors of FIGS. 1, 6, and 9.

FIG. 12 is a block diagram of an example implementation of acommunication adaptor of the modular monitor service of FIG. 6.

FIG. 13 is a block diagram of another example implementation of thecommunication adaptor(s) of FIG. 6.

FIG. 14 is a block diagram of an example implementation of apreprocessor module of FIG. 6.

FIG. 15 is a block diagram of a system illustrating a registrationprotocol for use with the system 100 of FIG. 1.

FIG. 16 is a sequence diagram illustrating an example implementation ofthe registration protocol of FIG. 15.

FIG. 17 is a flowchart illustrating example operations of the system ofFIG. 15.

DETAILED DESCRIPTION

FIG. 1 is a block diagram of a system 100 for monitoring smart itemdevices. In the example of FIG. 1, a sensor network 102 that includesvarious smart item devices provides real-world data to one or morebusiness data processing systems 104 in a timely and accurate manner,using a local area network 106 (although other sizes or types ofnetworks may be used). For example, the sensor network 102 may includesmart item devices 108, 110, 112, and 114, referred to herein as “smartitem devices” or simply as “devices” (or similar terminology), which mayinclude, for example, RFID readers (for reading RFID tags associatedwith real-world objects having an RFID tag), various embedded systems,and/or various types of sensors and/or sensor motes.

Although the following description refers primarily to the sensornetwork 102 or other sensor network(s) as an example implementation(s),it should be understood that such sensor networks may refer to anynetwork that gathers or obtains information, even if not all of thedevices of the sensor network do not have specific sensor functionalityassociated therewith (e.g., one of the devices of the sensor network 102may include an actuator). Moreover, it should be understood thatvirtually any network of devices may be used, alone or in conjunctionwith one another. Further, devices of such device networks maycommunicate with one another (e.g., in a peer-to-peer fashion), and/ormay communicate, e.g., through appropriate middleware, with the businessdata processing systems 104, or other systems.

In FIG. 1, the device 108 is illustrated as including a centralprocessing unit (CPU) 116, as well as a memory 118. Thus, the device 108should be understood to be capable of various levels of computingcapabilities, including, for example, processing or transmitting senseddata (e.g., in the case where the device 108 includes, or is associatedwith, a sensor). Although not specifically illustrated in FIG. 1 for thesake of clarity, it should be understood that the devices 110, 112, and114 also may include the same or different computing capabilities,including, for example, the capability to form and participate in thesensor network 102, such as a wireless network and/or a peer-to-peernetwork.

Thus, the sensor network 102 may be used to collect, process, filter,aggregate, or transmit data that may be useful to the business dataprocessing systems 104. For example, the business data processingsystems 104 may include inventory management systems, supply chainmanagement systems, retail store management systems, warehousemanagement systems, and any other system(s) that may be used to executebusiness processes with respect to real-world objects, where suchreal-world objects may include, for example, products for sale, palletsor other shipment elements, patients, or manufacturingmaterials/equipment. By tracking and analyzing such real-world objects,the business data processing systems 104 may be used, for example, todetermine inventory levels, set pricing levels, evaluate marketingstrategies, evaluate manufacturing or production technologies, reducetheft, or maintain safety.

By including smart item devices as, or in association with, the devices108, 110, 112, and 114 of the sensor network 102, processing may beperformed very early in the data-collection process(es), so that aburden placed on the business data processing applications 104 may bereduced or eliminated. For example, the business data processingapplications 104 may be located at a corporate headquarters, and thesensor network 102 may represent one of many (types of) networks thatmay be dispersed across a large geographical region connected by thewide area network 106. As such, for example, the business dataprocessing systems 104 may only require certain sub-sets orcharacterizations of data collected by the network 102 (and relatednetworks), and may not need or want all collected data.

In some implementations, the business data processing systems 104 mayinclude compound or composite applications that are made from re-usablesoftware components or services that are designed to perform somewell-defined task(s). Also, in these or other implementations, thebusiness data processing systems 104 may include legacy applicationsthat may not easily communicate with data-collection devices (or withother business data processing systems), and, in such cases, services orservice components may be provided as interfaces between the legacyapplications and the data collection devices and/or other systems. Thesystem 100 allows these and other applications and services to bedeployed directly on the devices 108, 110, 112, and 114, so that, forexample, services may be run on the devices (and data may be collectedand/or processed) in a timely, efficient, reliable, automated,cost-effective, and scaleable manner. Thus, for example, businessprocesses may be decomposed into individual services and deployed atdifferent devices.

The system 100 includes a service mapper 120 that is operable to selectthe device 108 as a selected device from among the plurality of devices108, 110, 112, and 114 of the sensor network 102, for deploying aservice 122 thereon, as shown. In so doing, the service mapper 120accesses a service repository 124 that is operable to store a pluralityof services that are eligible for execution within the sensor network102 and/or other networks (not shown in FIG. 1). The service mapper 120determines service metadata 126 along with an actual service executable128, and compares the service metadata 126 against device metadata 130associated with each of the plurality of devices 108, 110, 112, and 114.Based at least on the service metadata 126 and the device metadata 130,the service mapper 120 may select the device 108 as being particularlywell-suited for deployment of the service 122 (including the serviceexecutable 128) thereon.

For example, the device metadata 130 may include a description of eachdevice, the description being constructed according to an ontologyand/or schema that is known to the service mapper 120 and common to thevarious devices 108, 110, 112, and 114. Additionally, or alternatively,the device metadata 130 may be collected in a device-specific format orstructure for each of the devices 108, 110, 112, and 114, e.g., by asystem monitor 132, and may thereafter be converted into such a commonschema for use by the service mapper 120. For example, the devicemetadata may include a description of various technical capabilities ofthe devices 108, 110, 112, and 114, provided in an extensible MarkupLanguage (XL)-based language, e.g., by using an XL schema, as describedin more detail, below. Of course, other formats, languages, and/orstructures may be used, as well.

More generally, the device metadata 130 may include, for example, adevice description, a software description, a hardware description, anda device status. For example, the device description may include adevice name, identifier, or type, or may include vendor informationincluding a vendor name or vendor website. The software description mayinclude an operating system description, including version and/orvendor, or may include a description of services running or allowed torun on the device platform. The hardware description may includeinformation about attributes of the CPU 116 (e.g., name and/or speed),memory 118 (e.g., total and/or free amount of memory), or connectioncapabilities (e.g., connection speed or connection type) of thedevice(s). The device status may include more volatile information,including a device location, current CPU usage, or remaining power ormemory. Of course, other device aspects or information may be includedin the device metadata 130, as described below and/or as would beapparent. For example, the device metadata 130 may include informationabout other devices, such as where the device 108 includes an RFIDreader, and the device metadata 130 may include a description of typesof RFID tags that may be read and/or written to by the RFID reader.

The service metadata 126 may somewhat analogously include variousservice descriptions and/or requirements that relate to whether and howthe service(s) may be executed on one or more devices. For example, theservice metadata may include a service behavior description, technicalconstraints of the service, or information regarding input, output,preconditions, or effects (IOPE) of the service. For example, technicalconstraints may include a required CPU type or speed, an amount of(free) memory that is needed, a type or speed of connection that isrequired or preferred, an operating system version/name/description, ora type or status of a battery or other device power source(s).

Thus, as with the device metadata 130, distinctions may be made betweenstatic and dynamic service requirements, such as hardware requirements.For example, a static value such as a total memory or maximum processingspeed required by a service may be included, along with dynamic valuessuch as available memory/processing/power and/or a number or type ofother services that may be allowed to concurrently run on a devicetogether with the service(s) in question, at an execution time of theservice(s).

Using at least the service metadata 126 and the device metadata 130, theservice mapper 120 may map a given service onto the devices 108, 110,112, or 114 of the sensor network 102. Such a mapping is designed notonly to value-match various aspects of the service metadata 126 and thedevice metadata 130, where necessary (e.g., matching a required memoryspecified in the service metadata 126 with a device memory specified inthe device metadata 130), but also to enable and optimize a deploymentand execution of the service in question. For example, it may be thecase that both the device 108 and the device 110 are nominally orostensibly capable of running the service 122 (e.g., both devices 108and 110 may posses some minimum required values of memory, processingcapabilities, or power). However, it may be the case that the service122 is more power-hungry than memory-hungry (or vice-versa), so that theservice mapper 120 may map the service 122 to the device 108 if thedevice 108 is currently able to provide more power relative to the othercandidate device 110, even if the device 110 currently provides morefree memory than the device 108.

Once an appropriate service mapping has been performed, a serviceinjector (not shown in FIG. 1) may be used to install and start themapped service (e.g., the service 122) on the device 108. Such a serviceinjector also may be used, for example, to manage a life cycle of theservice(s), e.g., by performing service updates or stopping the servicewhen necessary.

As referenced above, during run-time of the system 100, the systemmonitor 132 is configured to determine, track, and/or provide a currentstate of the system 100. Such state information may include, forexample, which of the devices 108, 110, 112, 114 are currently availablefor service deployments, or what services are currently running on whichof the devices 108, 110, 112, 114. More generally, the system monitor132 may detect and collect device metadata 130, including static,discrete-dynamic, or continuous dynamic device metadata, as described inmore detail, below, as well as network metadata 140 related to thesensor network 102, also described in more detail, below. As should beapparent, monitor data such as the device metadata 130 and/or thenetwork metadata 140 may thus be made available to the service mapper120, the business data processing systems 104, and/or to a systemadministrator.

In the example of FIG. 1, the system monitor 132 is implemented using afour-tier architecture to provide for a scalable, distributed monitoringservice(s). That is, the system monitor 132 may be implemented using oneor more monitoring services, where the monitoring services may be storedin the service repository 124, and may be mapped, in whole or in part,to the sensor network 102 (and to devices associated with the sensornetwork 102) by the service mapper 120. Such a four-tier architecturemay be used in conjunction with algorithms described herein, so as toefficiently gather monitor data in a distributed system landscape, suchas that of the system 100.

Such monitor data may include, for example, the device metadata 130(which may include, for example and as described herein, connectivityinformation, battery life, or CPU/memory usage of the devices 108, 110,112, 114) and/or the network metadata 140. The network metadata 140 mayinclude, for example, various network parameters, particularly wheresuch parameters are dynamic and not necessarily discernable frominformation about any single device. One such example of the networkmetadata 140 may include available bandwidth on the sensor network 102.Other examples include network topology information, mobilitycharacteristics of the network as a whole, and reliability of networkconnections.

In some implementations, as described herein, such monitor services maybe implemented using a modular approach, in which a core monitor serviceis mapped to one or more devices included in, or associated with, thesensor network 102. Then, additional monitoring-related functionalitymay be provided to such devices using plug-ins, add-on services orservice components, or other service modules, which interact with thecore monitor service. As should be understood, the core monitorservice(s) and any supplemental monitor services may be mapped, forexample, using the service mapper 120 and based on, for example,application-specific requirements and relevant device metadata (e.g.,capabilities). In additional or alternative implementations, variousprotocols may be used to register new devices and deployed monitorservice(s) with the distributed monitoring service(s) in a fast, secure,energy-efficient, and reliable manner, even as devices join or leave thesensor network 102.

In the example of FIG. 1, then, the above-referenced four-tierarchitecture includes four types or classes of monitor services, whichmay be hierarchically layered. Specifically, the uppermost tier (alsoreferred to herein as the global layer), includes a global monitorservice (GMS) 132 a. The global monitor service 132 a provides ahighest-level storage and view of monitor data, not just for the sensornetwork 102, but potentially for a plurality of sensor networks (see,e.g., FIG. 2). Thus, for example, the global monitor service 132 a mayprovide a central contact point for system monitoring information forother system components (e.g., the service mapper 120), the businessdata processing system(s) 104, a system administrator, and/or a systemadministration graphical user interface (GUI). Global-level monitor datamay be stored in a memory represented in FIG. 1 by global monitor data136, which may thus be considered to represent or include global devicemetadata describing devices of the sensor network 102 and othernetworks, at least at a high level, as well as current serviceinformation about which services are running on which networks, forexample.

The global monitor service 132 a is conceptually above, and updated by,a second layer or tier, referred to herein as the local layer or localtier, and including a local monitor service(s) 132 b. The local monitorservice 132 b is configured to provide the global monitor service 132 awith information about changes in the underlying sensor network 102.Thus, the local monitor service 132 b may be configured to use a memoryrepresented in FIG. 1 as local monitor data 138 to store more detailedmonitor data about the devices 108, 110, 112, 114 in the sensor network102 than may practically be stored in association with the globalmonitor service 132 a (and the global monitor data 136). It should thusbe understood that the local monitor service 132 b may be responsiblefor one or more sensor networks or other device clusters, and that suchnetworks/devices may include potentially heterogeneous devices deployedin relatively close physical proximity to one another. Thus, the localmonitor data 138 may be considered to represent local device metadataregarding networks within the purview of the local monitor service 132,such as the sensor network 102, where it should be understood that thelocal monitor data 138 may generally be more specific than the globalmonitor data 136 with regard to particular devices of the sensor network102, and other supervised networks.

The third layer or tier includes a group leader monitor service 132 c,which may be configured for the collection, filtering, and aggregationof monitor data for the devices 108, 110, 112, and 114. In variousimplementations described herein, the group leader monitor service 132 cmay be configured to manage collection of monitor data from associateddevices 108, 110, 112, 114 by using, for example, polling or heartbeattechniques. The group leader monitor service 132 c is then responsiblefor reporting the resulting monitor data back to its respective localmonitor service 132 b. In the example of FIG. 1, the group leadermonitor service 132 c does not store monitor data, due to, for example,limited resources at the device 108, or because a rate of change of themonitor data processed by the group leader monitor service 132 c makesstorage impractical. Thus, the group leader monitor service 132 c may beconsidered to present group-level device metadata regarding theparticular devices 108-114 within its group, including, for example,dynamic or static device characteristics, or information about whichservices are running on which of the devices 108-114.

The fourth layer or tier of the example four-tier architecture of FIG. 1includes an edge monitor service 132 d. In the example of FIG. 1, theedge monitor service 132 d collects the monitor data for its associateddevice (here, the device 110) and the local services of the associateddevice. That is, it should be understood that, just as the device 108 isillustrated as executing the service 122, the device 110 also may beexecuting one or more services, and the edge monitor service 132 d maybe configured, for example, to monitor information about such services,as well as to monitor static or dynamic data specific to the device 110itself (e.g., total memory, currently-available memory, device type,and/or other device characteristics). The edge monitor service 132 d isfurther configured to report collected monitor data to the group leadermonitor service 132 c. Thus, the edge monitor service 132 d providesedge-level device metadata about a particular, (usually single) device,such as the device 110.

In the above-described architecture, the monitor services 132 a-132 dmay be configured to be responsible for different tasks, and maygenerally become more lightweight towards the edge of the infrastructureof the system 100. Consequently, for example, the edge monitor service132 d may be implemented on the device 110, which may have very limitedcomputing capabilities, while the global monitor service 132 a may beimplemented on a device(s) 142 and/or 144, such as, for example, apersonal computer (PC) or a similarly-powerful server machine.Meanwhile, the local monitor service 132 b may be implemented, forexample, on a device 146, such as, for example, a smart RFID reader, ora personal digital assistant (PDA). The group leader monitor service 132c may be deployed, as shown in FIG. 1, on one of the devices of thesensor network 102 (although it should be understood that the devices108, 110, 112, 114 may be heterogeneous devices having differingcomputing capabilities, so that the device 108 may be selected as thegroup leader based on, for example, its relatively-superior resources),or the group leader monitor service 132 c may be deployed, in anotherexample, on a wireless access point that is in communication with thedevices 110, 112, and 114. A number of different examples of how themonitor services 132 a-132 d may be physically deployed on some or allof the various devices 108-114, 142, 144 and/or 146, as well as otherdevices, are provided below with respect to FIGS. 2-3.

Some or all of the monitor services 132 a-132 d may be implemented usinga core monitor service 148 for certain fundamental monitoringfunctionality, in conjunction with a plurality of potential plug-ins,attachments, service components, or other modules, represented in FIG. 1by the monitor service module 150. In this way, for example, the monitorservice module 150 may be associated with the core monitor service 148within the devices 108 (and, analogously, although not shown in FIG. 1,within devices 142, 144, 146, and 110-114), such that the core monitorservice 148, which may be very slim so as to run on small orresource-poor devices, may be specialized/extended according toapplication-specific needs and/or the capabilities of the respectivedevices. Accordingly, for example, functionality related tocommunication, data storage, or data preprocessing may be added orreplaced to a given device without changing the core monitor service148. Although not shown specifically in FIG. 1, examples of uses of coremonitor service(s) and associated monitor service modules are discussedin more detail with respect to FIGS. 6-14

During operation, the system 100 may gather monitor data, including, forexample, the device metadata 130 or the network metadata 140, using thefollowing example algorithm. Specifically, the monitor data may begathered at the group leader monitor service 132 c, from which it ispropagated to the local monitor service 132 b, and then to the globalmonitor service 132 a. To gather data, the group leader monitor service132 c may execute a system adaptor 134, which may itself be, forexample, a service mapped to the device 108 from the service repository134 by the service mapper 120. The system adaptor 134, which mayconceptually represent a plurality of different types of adaptors, andwhich also may be considered to be an additional or alternative exampleof the monitor service module 150, may be configured to interface withthe service 122, and thereby may gather data from or about the service122. In other examples, the system adaptor 134 may represent a deviceadaptor that is configured to interface with the components of thedevice 108, e.g., the CPU 116 or the memory 118, so as to provide, forexample, hardware-specific information related to the device 108.

Thus, to gather data, the group leader monitor service 132 c may executethe system adaptor(s) 134, which thereby serve as data sources toprovide the monitor data regarding devices and services. For example, inexample of FIG. 1, the monitor data may include information about thedevice 108, and/or about the service 122. Via, for example, heartbeatmessages, the monitor data is sent to upper tiers, e.g., via the localmonitor service 132 b to the global monitor service 132 a. In exampleimplementations, the group leader monitor service 132 c collects monitordata from the edge devices 110, 112, 114. Specifically, each of the edgedevices 110, 112, 114 may be associated with its own monitor service,e.g., the edge monitor service 132 d of the edge device 110. As shouldbe understood, and as described in more detail below, any of the monitorservices 132 a-132 d may be implemented using (instances of) the coremonitor service 148, along with various examples and types of themonitor service module 150.

The group leader monitor service 132 d and the local monitor service 132b may be configured to perform message aggregation, in which messagesfrom different devices (e.g., from different group leader devices,and/or from different edge devices) are summarized into a singlemessage. At each of the group leader monitor service 132 c, the localmonitor service 132 b, and the global monitor service 132 a, the monitordata may be preprocessed (e.g., filtered or aggregated), and suchpre-processors may be performed by the monitor service module 150, or asimilar module. Accordingly, an amount of monitor data that is passed tothe global monitor service 132 a may be reduced.

In the architecture of the system 100 of FIG. 1, then, (updated) monitordata is propagated up from lower to higher tiers, e.g., from the edgemonitor service 132 d to the global monitor service 132 a. As shown, themonitor data may be stored in various forms and to various extents,within different ones of the tiers/layers. For example, as shown, datamay be stored at the global monitor data 136, and/or at the localmonitor data 138, where it should be understood that the local monitorservice 132 b and the local monitor data 138 (and the device 146) mayrepresent multiple services, memories, and devices associated with thesystem 100 (see, e.g., FIGS. 2-4).

Various techniques may be used to determine the type and extent of themonitor data that is to be stored (or not stored) at a given one of thetiers of the architecture of the system 100 of FIG. 1. For example,decisions on whether and where to store monitor data may be based onbattery lifetime, memory availability, device reliability, networkutilization, response times, and outdated information (e.g., there maybe a requirement to keep certain types of monitor date up-to-date to aspecified extent). For example, the device 146 associated with the localmonitor service 132 b may have a certain amount of available memory,while another device (not shown) may implement another local monitorservice associated hierarchically with the global monitor service 132 a,and which may have a relatively-significant amount of free memory.

One aspect of whether to store monitor data at a given location (e.g.,at the local monitor data 138 or the global monitor data 136) relates toa priority of the monitor data. For example, information such as adevice ID, a device classification, and alive-status may have a highpriority for being stored. Another aspect relates to a nature of themonitor data. For example, static and discrete-dynamic data from thegroup leader monitor service 132 c may be stored when queried, so thatoften-queried monitor data is read less often (e.g., is effectivelycached at the local monitor data 138). As another example, (potentially)outdated data must be managed, so as to be updated, as necessary.Meanwhile, continuous-dynamic data may not be stored, since it may beoutdated as soon as it is stored. Therefore, continuous-dynamic data maysimply be read (e.g., queried) from the relevant device, as needed.

The decision of whether and how to store monitor data at a givenlocation may be made dynamically, e.g., by evaluating an expression thatincorporates aspects such as, for example, hardware capabilities neededfor the storage, a proximity of the storage location to the sensor, or atype of information to be stored. For example, each device (e.g., thedevice 146) may compute a value, based on, e.g., an associated hardwareprofile, response time(s) for a query, a distance to the edge device(s)110-114, a data priority, and/or a dynamic type of the data (e.g.,static, discrete-dynamic, or continuous-dynamic). The resulting valuemay be defined using a mathematical expression (implemented, forexample, during registration of a particular service or device, where anexample of such registration is described in more detail, below, withrespect to FIGS. 7B and FIGS. 15-17), in which the considered aspectsare represented numerically and weighted for subsequent combination andcomparison to a defined threshold. An example of such an expression isshown in Eq. (1):

$\begin{matrix}{{{Device} - {capability} - {{describing}\mspace{14mu}{value}}} = {{\left( {{residual}\mspace{14mu}{lifetime}} \right) \times w_{1}} + {\left( {{CPU}\mspace{14mu}{speed}} \right) \times w_{2}} + {\left( {{CPU}\mspace{14mu}{utilization}} \right) \times w_{3}} + {\left( {{memory}\mspace{14mu}{size}} \right) \times w_{4}} + {\left( {{memory}\mspace{14mu}{utilization}} \right) \times w_{5}} + {\left( {{network}\mspace{14mu}{bandwidth}} \right) \times w_{6}} + {\left( {{network}\mspace{14mu}{utilization}} \right) \times w_{7}} + {\left( {{device}\mspace{14mu}{classification}} \right) \times w_{8}} + {\left( {{kind}\mspace{14mu}{of}\mspace{14mu}{information}} \right) \times w_{9}}}} & {{Eq}.\mspace{14mu}(1)}\end{matrix}$

In addition to the dynamic/automatic approach just described, a manualstorage decision may be made. For example, a system administrator maywant to define types or instances of monitor data that should or shouldnot be stored on designated device(s). For example, an administrator mayhave the authority to overrule the automated decision, above, and defineadditional or alternative storage rules. Such manual decisions may bemade, for example, for each specific device, or for each device type, orbased on the type/role of each monitor service (e.g., all local monitorservices 132 b may be required to store certain types of monitor data).

Finally with respect to FIG. 1, and again as described in more detailherein, e.g., with respect to FIGS. 7B and 15-17, it should beunderstood that a monitor service(s) (and associated device(s)) mayleave or join a network. For example, the device 110 may initially notbe a part of the sensor network 102, and may be a mobile or portabledevice that may be moved from one location to another. As such, thedevice 110 may be transported to a location of the sensor network 102,and the device 110 (e.g., the edge monitor service 132 d) may try toregister at the group leader monitor service 132 c, or at any devicethat is itself connected to the global monitor service 132 a.Accordingly, a dedicated protocol may be used for such registration, sothat devices and monitor services may easily or automatically beconfigured to leave one sensor network and join another. Examples ofsuch dedicated protocols are discussed in more detail, below, withrespect to FIGS. 15-17

FIG. 2 is a block diagram 200 illustrating an example deployment of thesystem 100 of FIG. 1. FIG. 2 illustrates that, as described above, thesystem 100 may be deployed across four conceptual tiers or layers, whichare represented in FIG. 2 as a global layer 202, a local layer 204, agroup layer 206, and an edge layer 208. As should be understood from thedescription of FIG. 1, the layers 202-208 have different tasks, and areeach associated with their respective type of monitor service (e.g., theglobal monitor service 132 a, the local monitor service 132 b, the groupleader monitor service 132 c, and the edge monitor service 132 d). Eachtype or class of monitor service may be associated with a physicaldevice (e.g., the device 144, 146, 108, and 110 of FIG. 1) based on thecapabilities of the device(s). As a result, for example, the relativelylight-weight edge monitor service 132 d may run on a device, e.g., asensor mote, with very limited computing capabilities, while the globalmonitor service 132 a may run on a device with significantly morecomputing resources, e.g., a PC or server.

In some example implementations, and as shown in FIG. 1, theabove-referenced variations in the monitor services 132 a-132 d may beachieved by way of a modular deployment of the monitor services 132a-132 d. For example, the edge monitor service 132 d may be deployed atthe edge layer 208 using only an instance of the core monitor service148, shown as core monitor service 148 d in FIG. 2.

Meanwhile, the group leader monitor service 132 c may be deployed usingan instance of the core monitor service 148 c, along with an instance ofa monitor service module 150, shown in FIG. 2 as the monitor servicemodule(s) 150 c. That is, it should be understood that the monitorservice module 150 c may represent one or more monitor service modules,where the monitor service modules are configured to implement themonitoring functionality described above with respect to the groupleader device 108 of FIG. 1. For example, the monitor service module 150c may be associated with aggregating monitor data (e.g., messages)received from all of the edge monitor services 132 d of the edge layer208, for reporting thereof to the local monitor service 132 b.

Along similar lines, the local monitor service(s) 132 b of FIG. 2 mayinclude the core monitor service 148 b, as well as the monitor servicemodule(s) 150 b, where the monitor service module 150 b may beconfigured to implement functionality associated with the local layer204 (e.g., storage of monitor data in the local monitor data 138, orupdating of the global monitor data 136). Finally, and similarly, theglobal monitor service 132 a may include the core monitor service 148 a,along with the global layer-specific monitor service module(s) 150 a.

It should be understood that FIG. 2 is merely an example, and that manyvariations are possible. For example, in some examples, the core monitorservices 148 a-148 d may be identical or substantially identical, whilein other examples, there may be substantial differences. For example,the core monitor services 148 a and 148 b may be different from the coremonitor services 148 c and 148 d, and, for example, may includefunctionality associated with data storage that is not required by thecore monitor services 148 c and 148 d, rather than relying on monitorservice modules 150 a and 150 b for this functionality. In otherexamples, the global monitor service 132 a may be implemented in anintegrated, non-modular manner, while the remaining monitor services 132b-132 d may use the modular construction described herein. Template(s)for the core monitor services 148 a-148 d may be stored in the servicerepository 124, so that the devices 144, 146, 108, 110 may receiveinstances of the core monitor services 148 a-148 d, as instantiated fordeployment, e.g., by the service mapper 120.

FIG. 2 also illustrates a hierarchical nature of the system 100. Thatis, in FIG. 2, the global monitor service 132 a is maintained over, andin communication with, a plurality of local monitor services 132 b, eachof which may itself be maintained over, and in communication with, aplurality of group leader monitor services 108. Finally, as alreadyillustrated in FIG. 1, each group leader monitor service 132 c may bemaintained over, and in communication with, a plurality of edge devices132 d.

In FIG. 2, as contemplated in the example of FIG. 1, it may be the casethat each monitor service 132 a-132 d is deployed on a single physicaldevice. More generally, however, it may be the case that a plurality of(types of) physical systems or devices are associated with one of thelogical tiers or layers 202-208. Conversely, it may be the case that aplurality of the layers 202-208 may be associated with a single (typeof) physical system or device.

FIG. 3 is a block diagram 300 illustrating a second example deploymentof the system 100 of FIG. 1, in which the layers 202-208 may beassociated with a plurality of (types of) physical systems or devices.In the example of FIG. 3, a company server 302 (e.g., a company-widecentral server) may be located in a first geographical location (e.g.,Europe), and may implement the global service monitor 132 a.

Meanwhile, a production plant server 304 (e.g., a server computerimplemented/located at a production plant for the company) may belocated at a production plant of the company in, e.g., San Francisco.The production plant server 304, along with a Stargate computer 306(e.g., a single board computer with communications and sensor signalprocessing abilities) and a WiFi access point 308, may be implemented atthe local layer 204. In other words, one or more local monitorservice(s) 132 b may be implemented using one or more of the physicaldevices 304-308.

In the example of FIG. 3, at least two local monitor services 132 bshould be understood to be included, e.g., with respect (at least) tothe Stargate 306 and the WiFi access point 308. That is, each such localmonitor service is maintained over at least one group leader monitorservice, which should be understood to be running on a sensor mote 310and a PDA 312, where the sensor mote 310 is the group leader to aplurality of sensor motes 314-318 (the sensor motes 314-318 thusillustrating, potentially, examples of the (edge) devices 110-114).

In the example of FIG. 3, then, more than four physical layers exist,and these physical layers may be mapped onto the four logical tiers orlayers 202-208 of FIG. 2. Thus, multiple physical system layers may fillin the role of one conceptual tier. In examples using more than fourphysical layers, devices may route information between conceptual tiers.For example, an edge device may route information from the local monitorservice 132 b to the group leader monitor service 132 c, even where theedge device in question may belong to a different sensor network, butmay be physically closer to the local monitor service 132 b than is thegroup leader monitor service 132 c.

As referenced above, however, physical systems/devices also may haveless than four tiers. For example, there may be only two physical tiers,in which case the global monitor service 132 a may be deployed on afirst device, while the local monitor service 132 b, the group leadermonitor service 132 c, and the edge monitor service 132 d may bedeployed on a second device, perhaps with a single, combined instance ofthe monitor service(s) 132 b-132 d.

In the examples of FIGS. 1-3, the hierarchy of devices may beconceptually tree-structured, e.g., each device may have exactly oneupper (or same) layer monitor service to report to (which may bereferred to as a “parent monitor”). The global layer device, e.g., thedevice 144, which contains the global monitor service 132 a, may be theonly monitor service without such a parent monitor. For purposes ofcollecting monitor data, edge devices (e.g., the edge devices 110-114)may not need to communicate with one another directly, but, rather, maysimply forward monitor data to their parent device(s). Of course, inthese or other contexts, devices may communicate directly with oneanother (e.g., in a peer-to-peer fashion, perhaps to calculate anaverage temperature in a room or to perform other collaborativecomputing).

More generally, devices may be physically connected to other devices inthe same network or may be connected to several networks. Thus, in otherimplementations, the monitor services 132 b-132 d may have severalparents. In some additional or alternative implementations, there may beexactly one main network connection, as referenced above and defined asthe connection with the shortest path (in terms of hops) to the globallayer device 144. Other connections (e.g., peer-to-peer and/or multiplenetwork connections) may be regarded as auxiliary or “shortcut”connections, so that, for example, a local-layer device with the localmonitor service 132 b on a first sensor network need not go through theglobal layer to communicate with an edge device of a second sensornetwork, but, rather, may communicate with the edge device using anintervening group leader device.

FIG. 4 is a block diagram of a smart items infrastructure 400 forimplementing the systems of FIGS. 1-3. The smart items infrastructure400 includes five layers: a device layer 402, a device level servicelayer 404, a business process bridging layer 406, a system connectivitylayer 408, and an enterprise application layer 410. The layer 402 may beconsidered to contain various ones of the devices 108, 110, 112, and 114of FIG. 1, or similar devices, across a number of groups, local networksand/or physical locations. Meanwhile, the layers 406, 408, and 410 maybe considered to be part of, or associated with, the business dataprocessing systems 104 of FIG. 1. Thus, the layer 404 may be consideredto represent remaining components of the system 100 of FIG. 1, e.g., theservice mapper 12, the system monitor 132 and/or the monitor services132 a-132 d, and the service repository 124, as shown in FIG. 4.

The device layer 402 thus comprises the actual smart item devices, aswell as any communications between them. The device layer 402 also isresponsible for presentation of any offered hardware services to thenext higher layer, the device level service layer 404. The devices mayinclude, for example, an RFID device 412, embedded systems 414, sensornetworks 416, and any other new or emerging technologies 418, as wouldbe appropriate. It should be understood that the examples of the devicelayer 402 are non-limiting, and may overlap. For example, sensornetworks may include RFID devices (readers/tags), embedded systems,and/or other emerging technologies.

For the RFID device(s) 412, mobile tags may be attached to real-worldobjects, and are then read (and optionally written to) by RFID readers.In an implementation using active tags, the active tags may also provideadditional sensor data (e.g., a current value or a past value). In RFID,communication is typically initiated by the reader, while tags may ormay not directly communicate with each other. Such an RFID reader may beconfigurable to the extent of processing tag data, e.g., may beconfigured to perform verification of written data, or to avoidreporting a disappearance of a tag if the ostensibly lost tag in factreappears within a given time window.

Techniques for communicating with the embedded systems 414 may vary onthe types of devices of the embedded systems. For example, the embeddedsystems may represent anything from small-scale, one-chipmicrocomputers, all the way to full-blown PC hardware. Thus, forexample, for devices that have the capabilities of a mobile phone ormore (e.g., are able to run a Java Virtual Machine™), implementation maybe performed in Java™ or based on OSGi (the latter representing a knownframework for implementing a component model for remote installation andmanagement of applications and/or application components). As alsodescribed above, the sensor networks 416 may include any number of typesof sensors that may include integrated processing power and that may beable to execute peer-to-peer communication.

The service repository 124 may store at least two kinds of services,compound and atomic services. The compound services generally rely onother services to fulfill their tasks, and may have nodirectly-executable code of their own; rather, the compound services mayinclude an executable service composition description that is stored ina corresponding service description. Thus, compound services may haveone service executable, i.e., the service composition description. Incontrast, atomic services do not generally use other services, and havetheir own directly-executable code. Also, as mentioned above, since anatomic service may be deployable on different platforms, an atomicservice may have more than one service executable, e.g., may have aservice executable for each of the different platforms.

The service repository 124 also may store the service metadata 126,where such service metadata 126 is described in detail, above, and mayinclude a service name, identifier, version, or vendor, or may describerun-time requirements of the service, including, for example, technicaldeployment requirements (e.g., high bandwidth, or minimum processingpower required), semantic requirements (e.g., that a receiving devicehave a serial connection and/or many device neighbors), and spatialrequirements (e.g., that a receiving device be in the basement, or at asouth side of a specified building).

Finally at the device-level service layer 404, a device repository 420may be included. As should be understood from the above description, thedevice repository 420 may include, for example, information aboutdevices (e.g., the device metadata) in an manner analogous to that inwhich the service repository 124 maintains information about services(e.g., the service metadata). For example, device metadata may be storedin the device repository 420 based on communication with the systemmonitor 132 (e.g., with one or more of the monitor services 132 a-132 d.In other example implementations, the device repository may includedevice metadata stored by an administrator based on externally-availableinformation about the devices. For example, as already mentioned, thedevice metadata may include a device name, power capacity, memorycapacity, processing capacity, or other information that may be relevantto mapping (and ultimately deploying) a service to an associated device.Of course, in these examples, the device repository 420 may includegenerally static or high-level device metadata, and/or may include someor all of the global monitor data 136 and/or the local monitor data 138.

At run-time, the system monitor 132 monitors a current system state, asalready described, using the monitor services 132 a-132 d. Whether andhow any part of a state of a service is exposed to the system monitor132 may be set by a developer of the service at design-time. Thisstate-availability information may thereafter be available both to asystem administrator and to the service mapper 120. As also describedabove, the service mapper 120 receives deployment requests and thendetermines on which device(s) the corresponding service should bedeployed, e.g., by matching the service metadata to the device metadata,which may include a current state of the smart item devices and relatedlocal network(s). As also described herein, the service mapper 120 alsomay react to certain events or conditions, including changes in thenetwork state (as recognized by the system monitor 132), and maythereafter decide to re-map a service or add or remove instances ofservices to better fulfill given deployment requests/requirements.

The business process bridging layer 406 includes services designed toaggregate data from the devices at the device layer 402, provided viathe device level service layer 404, and to transform the data from thedevice layer 402 into business-relevant information. In so doing, anamount of data sent to back-end enterprise application systems may bereduced, and business logic may be executed for different ones of theenterprise application systems.

For example, one or more rule processor(s) 422 may be used to parseincoming messages, support basic operational services (e.g., itemmovement, association, de-association, or device reading/writing) andsupport information querying. The rule processor 422 processesuser-defined business rules that define or reference any other basicoperational services that should be executed or consulted. Using suchrules and basic operational services provides a flexible framework toadapt the system 400 to different business scenarios.

The rule processor 422 may use a data repository 424 for keeping trackof all physical objects of interest, e.g., for keeping track of thecurrent state, location, timestamp, or associated business transactionof a given object being tracked, as well as for keeping track of whatfuture actions are expected. Aggregated information from the datarepository 424 may be reported on a regular basis, e.g., daily ormonthly.

One example of an operation of the layers 402, 404, and 406 includes a“goods receiving” scenario. For example, a provider delivering objectsto a receiver may send an Advanced Shipment Notification (ASN)containing a list of all objects in the shipment, along with objectidentifiers such as Electronic Product Codes (EPCs). The ASN may bestored in the data repository 424. When the shipment arrives and passesthe RFID readers at the device layer 402, e.g., at a receiving dockdoor, then the EPCs are read by the RFID readers, and sent to the ruleprocessor 422. The rule processor looks up the ID of the reader fromwhich the message came, determines a location and role of the reader,and then calls the appropriate basic operational service responsible forhandling received shipments. This operational service compares theobtained EPCs with the expected EPCs from previous ASNs, and, if a matchis found, reports to an enterprise application 432 that the delivery hasarrived and is complete. The executed operational service also may thenupdate the data in the data repository 424. Services described above, aswell as services for receiving and sending the involved messages, may bemanaged by a service manager 426.

Components in the system connectivity layer 408 may be used to connectdifferent application systems and to support system and dataintegration. For example, messages and data may be routed to the correctbackend systems by an information exchange and transformation module428, and also may be transformed thereby to enable asemantically-correct integration. On top of message-routing andtransformation services, the system connectivity layer 408 also providesservices in a service repository 430 that can be used to access thefunctionality provided by the Business Bridging Layer 406 by enterpriseapplications 432.

The enterprise application layer 410 includes, for example, traditionalenterprise IT systems responsible for controlling and managingenterprise business applications. An enterprise application 432 coveringa specific business process may not be a single program, but rather maybe composed of different services that work together to achieve adesired functionality. Such services may be provided by the sameenterprise system, by another enterprise system within the enterpriseapplication layer 410 (possibly located at a site of a businesspartner), or by systems from lower layers (e.g., by smart item devicesat the device layer 402).

Finally in FIG. 4, development tools 434 may refer to tools for creatingenterprise application(s) 432 and other applications/services. Using adevelopment environment integrated with the infrastructure 400 maysupport the implementation of basic services in manners that are similarto known development tools in the enterprise application space. Further,the development tools 434 may allow the creation of the required servicemetadata 126, as well as the inclusion of existing services into newapplications. Furthermore, the development tools 434 allow a developerto specify where a certain service should run, to configure individualservice instances, and to deploy the services in a desired manner. Thatis, a developer may develop service metadata/executable(s) 436 using thedevelopment tools 434, and may then provide desired ones of the servicemetadata/executable(s) 436 for storage in the service repository 124,and/or for mapping/re-mapping by the service mapper 120 at the same orlater time.

Having described the above example implementations and settingsassociated with the system 100 of FIG. 1, FIG. 5 is a timing diagramillustrating an example algorithm for gathering monitor data using thesystem 100 of FIG. 1. The algorithm of FIG. 5 is implemented using theglobal monitor service 132 a, which, as already described, is configuredto gather information about all devices and services within itsunderlying hierarchy, and which thus provides a global system landscapeview. In the context of FIG. 4, the global monitor service 132 a may runas a part of the device level service layer 404 and/or the businessprocess bridging layer 406 of the infrastructure 400 of FIG. 4. Theglobal monitor service may be requested/called by high-level servicesthat also are running at the device level service layer 404 or thebusiness process bridging layer 406, or through separate device andservice monitoring graphical user interfaces (GUIs).

As referenced above, the local layer may include a plurality of thelocal monitoring services 132 b, which are each configured to gathermonitor data from edge devices, using, for example, polling andheartbeat techniques, as described in more detail, below. The localmonitor service 132 b is configured to manage collected monitor data,including, for example, filtering, aggregating, and storing the monitordata. The group layer includes multiple devices at or near the edge ofthe infrastructure (e.g., the infrastructure 400 of FIG. 4) which fillin the role of the group leaders, such as the device 108 of FIG. 1. Thegroup leaders gather information about edge devices (e.g., devices110-114) in their vicinity having the edge monitoring service 132 dinstalled. In the example of FIG. 5, monitor data obtained by the groupleader (e.g., 108) is not stored at the group leader, but may befiltered, aggregated, or otherwise processed, before being forwarded tothe local monitor service 132 b to be stored. Finally, devices (e.g.,devices 110-114) run the edge monitor service 132 d and form the edgelayer. In some implementations, group leader monitor services 132 c andedge monitor services 132 d may be essentially identical in terms ofproviding, preprocessing, and not storing monitor data, although theedge monitor service 132 d is not responsible for managing otherdevices. In the example of FIG. 5, the edge monitor service 132 d isconfigured to provide monitor data and send it to its group leader usingheartbeat messages (e.g., messages sent using an active send queue atsome pre-defined interval). More generally, however, gathering monitordata from edge layer devices may be triggered either by timers of theedge devices for sending the heartbeat messages, or by poll messagesreceived at the edge devices from upper tiers/layers.

In the example of FIG. 5, a timer triggers the local monitor service 132b to check for outdated data in the local monitor data 138, whichresults in polling (502) several edge layer devices. The local monitorservice 132 b does not communicate directly with the edge layer devices,but rather uses the group leader device 108 at a gateway, and thus sendsa polling message to the group leader monitor service (504). The groupleader monitor service 132 c splits the single poll message intodifferent poll messages (although FIG. 5 shows only one poll message,for the sake of simplicity), which are sent to the individual edge layerdevices 110-114 (506).

Each edge layer device 110-114 reads a local system adaptor (508), whichshould be understood to be the same or similar to the system adaptor 134of FIG. 1, to obtain up-to-date monitor data. Examples of systemadaptors and related elements are provided in more detail below, withrespect to FIGS. 9-11. Generally, however, it should be understood thatsuch system adaptors serve as data sources to provide monitor data abouttheir respective edge device, as well as about any service(s) running ontheir respective edge device.

The edge monitor service 132 d then executes preprocessing (510) of themonitor data (e.g., filtering and/or aggregation). Then, without storingthe pre-processed monitor data, sends a heartbeat message (512) with thepre-processed monitor data to the group leader monitor service 132 c.The group leader monitor service 132 c receives messages with themonitor data from a plurality of edge devices, and provides furtherpre-processing (514), including, for example, calculation of an averageof the CPU utilizations of all managed edge devices. Then, the groupleader monitor service 132 c performs message aggregation (516), inwhich messages from different devices are summarized into a singleheartbeat message for transmission to the local monitor service 132 b(518).

The local monitor service 132 b receives such heartbeat messages from aplurality of group leader monitor services 132 c, and performspre-processing (520), including, e.g., filtering of non-critical data,and/or aggregation thereof. The pre-processed message(s) are then stored(522), e.g., at the local monitor data 138. Then, a timer of the localmonitor service 132 b triggers a heartbeat indicator (524) that causesthe local monitor service 132 b to compute a delta synchronization (526)between the local monitor data 138 and the global monitor data 136. Thatis, the local monitor service 132 b determines which relevantinformation within the local monitor data 138 has been changed orupdated as a result of the execution of the monitoring algorithm of FIG.5, and only this changed data is submitted to the global monitor data136, e.g., as part of a delta synchronization message (528). In thisway, an amount of transferred and processed data is reduced. Inadditional or alternative implementations, the delta synchronization maybe initiated by a message from the global monitor service 132 a to thelocal monitor service 132 b.

Finally in FIG. 5, the updated data is preprocessed by the globalmonitor service 132 a (530), and stored in the global monitor data 136.Then, the business data processing systems 104, e.g., supply chainmanagement applications, may access the data from the global monitordata 136. It should be understood from the above description thatmonitor data from a given edge device is stored in the landscape tree onthe path from the edge device itself to the global monitor service 132a. As a result, the monitor data is easily located for use or deletionthereof.

FIG. 6 is a block diagram of a modular monitor service 600 that mayrepresent one or more of the monitor services 132 a-132 d of FIG. 1.That is, the modular monitor service 600 includes the core monitorservice 148, which is illustrated in FIG. 1 in the context of the groupleader monitor service 132 c, but which, as explained above, also may beimplemented in the context of some or all of the remaining monitorservices 132 a, 132 b, and/or 132 d. The modular monitor service 600also includes the monitor service module 150, which, again, isillustrated in FIG. 1 in the context of the group leader monitor service132 c, but which, again, also may be implemented in the context of someor all of the remaining monitor services 132 a, 132 b, and/or 132 d.

Thus, the core monitor service 148 may be configured to implementfundamental functionalities that may be used by most or all of themonitor services 132 a-132 d (e.g., query routing, role-based datahandling, and coordination of communication with other monitor servicesrunning on other devices), while the monitor service module(s) 150 maybe configured to implement functionality that may be more particular toa given one of the monitor services 132 a-132 d. The monitor servicemodule(s) 150 may thus be implemented as plug-in components that areadded to the core monitor service 148 on an as-needed basis, so that thecore monitor service 148 may be specialized according to individualneeds and capabilities of each monitor service and/or device.

For example, in the example of FIG. 6, the monitor service module(s) 150include the system adaptor 134, a communication adaptor 602, a datastorage module 604, and a data preprocessor 606. Consequently,associated functionality for these plug-ins, and other functionality,may be added or replaced to the module monitor service 600, withoutchanging the core monitor service 148. Moreover, as described in moredetail below, the monitor service module(s) 150 of the same category(e.g., different instances of the communication adaptor 602 or of thedata storage module 604) may share a common interface, so that the coremonitor service 148 need not be aware of the usage of the differentinstances/plug-ins.

Further in FIG. 6, module manager(s) 608 may be used to manage modulesof the same category. For example, the module manager(s) 608 may includea manager for the system adaptor(s) 134, and may be configured to selectand implement an appropriate one of the system adaptor(s) 134, based ona current situation and/or need of the core monitor service 148.Specific examples of such a system adaptor manager are provided below,e.g., with respect to FIGS. 9 and 10, and other examples of modulemanagers 608 are also discussed. It should be understood that the modulemanager(s), in some implementations, may act as actual intermediaries tomessages between the core monitor service 148 and a given monitorservice module 150, e.g., forwarding the messages from the core monitorservice 148 to the appropriate monitor service module 150, or viceversa. In other implementations, the module manager(s) 608 may beconfigured to load or select an appropriate one of the monitor servicemodule(s) 150, and may then remove itself from further communications.

FIG. 7A is a flowchart illustrating an operation of the system 100 usingthe modular monitor service 600. In FIG. 7A, instances of the coremonitor service 148 are deployed onto one or more of the architecturaltiers (702), e.g., of the system 100. For example, the service mapper120 may be configured to deploy the core monitor service 148 onto thedevices 108-114, 146, and 144 of the system 100, perhaps during aninitial set-up of the system 100. In another example(s), discussed inmore detail below with respect to FIG. 7B and FIGS. 15-17, the servicemapper 120 may map an instance of the core monitor service 148 onto anew device (not shown in FIG. 1) that comes into an area of the sensornetwork 102, and that wishes to communicate with one or more of thedevices 108-114, 146, and/or 144.

It should be understood that the core monitor service 148 may be storedin the service repository 124 as a template, form, or other genericstructure, and that different instances of the core monitor service 148may be deployed within the system 100. Moreover, the instances need notbe exactly identical. For example, different instances of the coremonitor service 148 may be deployed, having different functions includedor enabled, depending on which layer of the system monitor 132 theinstance is to be deployed. The service mapper 120 may execute theservice mapping of instances of the core monitor service 148 asdescribed above, e.g., based on the device metadata 130.

Once the core monitor service module 148 is installed within the system100, various monitor service modules may be installed (704). Forexample, the monitor service modules 134, 602, 604, and/or 606 may beinstalled, depending, for example, on the device metadata 130 associatedwith the device(s) in question, and/or onto which level of the monitorarchitecture the monitor service module(s) are being deployed. As isalso discussed in more detail below, such device metadata may beobtained using the already-installed core monitor service 148, and/ormay be obtained from memory.

With the core monitor service 148 and the monitor service module(s) inplace, monitor data may be collected, e.g., by implementing thealgorithm of FIG. 5 using the modular monitor system 600 of FIG. 6. Forexample, from the above discussion of FIG. 5, it should be understoodthat raw monitor data (e.g., at the edge monitor service 132 d) mayinitially be collected using the core monitor service 148 and/or thesystem adaptor 134 (706) (which, as described in more detail herein,e.g., with respect to FIGS. 9-11, may include both service and deviceadaptors). In this way, the raw monitor data (e.g., regarding relevantservices and/or devices) may be provided in a way that hides differentinterfaces of the (heterogeneous) services/devices, and that isextensible for new services/devices. Further, system standards, such as,for example, OSGi or JSR82, may be implemented.

The raw monitor data may be pre-processed at the pre-processor module606 (708). Examples of such pre-processing are provided in conjunctionwith FIG. 5, and further with respect to FIG. 14. Generally, however,such pre-processing acts on incoming data to reduce an amount of data tobe sent over the network connection(s), using, e.g., filtering andaggregation.

The (pre-processed) monitor data may be stored using the data storagemodule(s) 604 (710). For example, the data storage module 604 may beconfigured to hide different types of storage that may be available(e.g., file system, database, or in-memory data structure). As describedabove, storage of monitor data may be limited just to the local monitorservice 132 b and the global monitor service 132 a, so that,accordingly, the data storage modules 604 may be deployed only ontothose monitor services, and resources are conserved.

The processed and stored data may be propagated, and queries for newdata (e.g., by polling) may be executed using the communications adaptor602 (712). For example, as should be understood, the communicationsadaptor 602 may be configured to ensure communication betweenservices/devices, may hide unreliable or out-of-order data transfers,and may hide the core monitor service 148 from effects of differentcommunications protocols/hardware. In some implementations, thecommunications adaptor 602 may be considered to be separate from themonitor service 132 a-132 d, and, e.g., may be deployed separately(i.e., at separate times) from either the core monitor service 148 ormonitor service modules 134, 602, or 606. Different operations and usesof the communications adaptor 602 are provided below, with respect tothe examples of FIGS. 8, 12, and 13.

FIG. 7B is a flowchart illustrating additional example operations of thesystem 100. In FIG. 7B, it is assumed that the core monitor service 148is not initially installed. In many cases, however, the core monitorservice 148 may be needed in order to proceed with further operations ofthe system 100. For example, during a registration process of a newdevice within the system 100, registration protocol may requireinstallation and availability of the core monitor service 148 (see,e.g., the examples of FIGS. 15-17 for a discussion of an exampleregistration protocol for registering a new device with the system 100).In this and other scenarios, a bootstrapping technique may beimplemented, in which the core monitor service 148 is installed first,and then information from the installed (executing) core monitor service148 may itself be used to register the new device, and/or to deploy themonitor service modules 134 and/or 602-606.

For example, it may first be determined whether the device in questionsupports existing standards for deploying services (714) (e.g., OSGI,Jini, Services and Networks for Domotic Applications (SENDA), servicemanagement module (SMM), or JSR232). If such standards are not supportedby a device in question, then appropriate action may be taken. Forexample, in a case where the device is of a level of a mobile phone orPDA, then a user thereof may be instructed to execute an installationwizard (e.g., follow a link to download and start an installationprogram) for setting up the core monitor service 148 (716). In such acase, and/or using known deployment standards, and if the core monitorservice 148 is not yet installed (718), then static device metadata maybe determined (720), e.g., using the standards and/or from a memory.

At this point, the core monitor service may be installed (722), andadditional monitor data may be obtained therefrom (724). As described inmore detail below, e.g., with respect to FIGS. 15-17, a full-scaledevice registration with the system monitor 132 also may be executed atthis point, if necessary. Using the additional monitor data, appropriatemonitor service module(s) 150 may be deployed (726), so that collectionand/or transmission of additional monitor data may proceed.

FIG. 8 is a block diagram of an example implementation of the coremonitor service 148. In the example of FIG. 8, a communicationabstraction layer, with incoming 802 a and outgoing 802 b messages, maybe used by the core monitor service 148, for example, to establishconnections to monitor services on different devices, or to establishconnections to GUI interfaces and to other types of services. Thecommunication abstraction layer 802 a, 802 b is discussed in more detailbelow, with respect to FIG. 12. As should be apparent from FIGS. 6 and7, other module managers 150 (e.g., system adaptor manager, describedwith respect to FIGS. 9-11) also may be in communication with the coremonitor service 148, and, depending on how such managers are defined andimplemented, may overlap with some of the functionality of thecommunication abstraction layer(s) 802 a, 802 b.

The core monitor service 148 of FIG. 8 includes a query router 804. Thequery router 804 may be responsible, for example, for gathering andreturning queried monitor data, which may either be queried by (other)monitor services 132 a-132 d running on other devices, or by otherservices (e.g., temperature detection services, item tracking services,or other data-collection services).

A system landscape database 806 is included and activated in the FIG. 8example of the core monitor service 148 (e.g., the core monitor service148 may be associated with the global monitor service 132 a or the localmonitor service 132 b, in which case the system landscape database 806may represent, include, or otherwise be associated with the globalmonitor data 136 or the local monitor data 138, respectively). In thiscase, the query router 804 may attempt to obtain the requested monitordata from the system landscape database 806.

If the desired monitor data, or other desired data, is outdated or notfound, the query monitor 806 may query the desired monitor data from amonitor service running on a parent device, e.g., a different devicethat manages the device that is implementing the core monitor service148 (for example, the group leader monitor service 132 c may query thelocal monitor service 132 b, or the local monitor service 132 b mayquery the global monitor service 132 a). In another situation, thecurrent monitor service 148 may manage the queried system (i.e., is aparent to the queried system), in which case a lower level monitorservice will be addressed to collect the desired monitor data. In yetanother scenario, the queried device may be unknown to the core monitorservice 148 of FIG. 8, in which case the query may be forwarded to theupper layer which manages more systems, and, ultimately, may proceed tothe global monitor service 132 a, which may then forward the query tothe appropriate local monitor service 132 b.

Query routing may be straightforward if a target system (service ordevice) may be addressed directly, with no intervening system(s). Incases where there is no direct connection to the target system, thenintervening hops on the routing path are determined. Routing informationdescribing such intervening hops may be fetched from stored topologyinformation (which may be stored in the system landscape database 806,or in separate routing tables).

For example, each monitor service 132 b-132 d is provided with a parentmonitor service that is assigned during registration of the monitorservice (see, e.g., FIGS. 15-17, below). This child-parent informationmay be stored in the system landscape database 806, and/or in othermemory, as a property, from which a tree-shaped topology may begenerated. The tree-shaped topology may be traversed to determine thenext hop. In other implementations, the next/intervening hop may beobtained from a routing table, using an appropriate table look-up.Generally, such separate routing tables may use more memory thandetermining the routing information from the tree-shaped topology, butmay be more efficient and/or faster.

Entries in the routing tables may be changed only when devices connector disconnect from the system 100, in order to reduce a number ofrequired changes. To reduce the number of entries in the routing table,a next hop may be added only if the next hop is not the parent monitorservice, since, the next hop may be assumed, by default, to be theparent monitor service. In this way, a number of entries in the routingtables may be reduced to the number of systems that aremanaged/monitored by the monitor service, along with those that aredirectly connected thereto.

An algorithm for the query routing is illustrated below in Code Section1, which embodies the query routing guidelines just described.

Code Section 1 Query landscape: get the queried data If data not found  if information is requested about the current device     get systemadaptor to service or device     get information from adaptor else(information is not about the current device)   Query landscape: isdevice managed by this device?   If device is managed by this device    get child device to ask     get data from child device by asking themonitor on lower tier   else (device is not managed by this device)    get parent device to ask     get data from parent device by askingthe monitor on higher tier if data still not found   return error else(data found)   return data

Generally speaking, as already described, Code Section 1 is consistentwith a querying algorithm in which a request for monitor data isreceived at a (current) device. If the monitor data is related to thecurrent device, but not in the system landscape database 806, then thesystem adaptor 134 may be used to obtain the monitor data, as describedherein. Otherwise, if the monitor data is about another service/device,but is not in the system landscape database 806, then a parent or childmonitor service may be queried, as appropriate. If the monitor data isfound in either the system landscape database 806 or the parent/childmonitor service, then the monitor data may be checked to see whether itis up-to-date. If not, then additional polling/queries may be executedto obtain updated monitor data.

The core monitor service 148 also includes a ping requestor 808, whichis configured to be used by the global monitor service 132 a and/or thelocal monitor service 132 b, or any monitor service that stores monitordata in some type of monitor data storage/memory (e.g., the systemlandscape database 806). The ping requestor 808 may thus be configuredto ping devices in the system landscape, thereby to assist in keepingsystem landscape data of child systems up-to-date, and to detectdisconnected devices (and mark the data as ‘in doubt’). If a monitorservice does not store status information in a local monitor datastorage, e.g., the group leader monitor service 132 c or edge monitorservice 132 d, then the ping requestor 808 may be omitted ornon-activated.

The ping requestor 808 may be activated by a timer, and, in response,may determine all connected and managed child-systems from themonitoring data storage (e.g., from the system landscape database 806).For example, for all the systems, the ping requestor 808 compares thetime when the last life-signal was received to the current time, inorder to detect outdated monitor data (or other stored information). Ifoutdated, then a status of the system(s) may be changed to so indicate,e.g., may be changed from “alive” to “outdated.” If the timestamp isolder than a certain cut-off point, then the status may be changed from“outdated” to “in-doubt,” so as to indicate the possibility that thedevice in question is disconnected. For all “outdated” systems, the pingrequestor 808 sends a ping-request. The ping requestor 808 receives theping-response and updates the “last seen” timestamp accordingly, andthen changes the relevant status back to “alive” within the systemlandscape database 806.

An algorithm consistent with the above explanation of the ping requestor808 is provided below in the context of Code Section 2:

Code Section 2 Landscape query: get all systems and their status For allsystems do   If the timestamp is old enough to mark the system as“in-doubt”   then     Mark all related data as “in doubt” Else if it isold enough to mark the system as “outdated” then do so If the status is“outdated” then   Send a ping signal to this system

Although FIG. 8 is discussed in terms of the ping requestor 808, itshould be understood that other techniques may be used for determining astatus of elements of the system landscape of the system 100, e.g.,other echo requests used to test a reachability of the system(s) and/orto test network delays. Further, it should be understood that the coremonitor service 148 also may receive, and thereafter respond to, pingrequests from other monitor services, as shown. Actual implementation ofa transport protocol that ensures reliable data transfer of the ping (orother) status requests may be implemented as a task of the communicationadaptor 602, as discussed in more detail below, with respect to FIG. 12.

The core monitor service 148 also includes a heartbeat transmitter 810,which may be implemented as a service configured to send a heartbeatmessage to a parent monitor service, so as to indicate that the device(on which the core monitor service 148 is deployed) is still running.The heartbeat transmitter 810 may be triggered by a timer, where thetime interval between two messages may be defined in associatedheartbeat settings. The interval may be chosen with respect toresource-constraints, so that small devices with limited power supplyand network capabilities may use a greater time interval than morepowerful devices (e.g., well-connected servers). A metric may be used todefine a default interval customized for each device type (e.g., for asensor device, PDA, or laptop). Additionally, the value of the intervaland other associated settings may be adjustable by the user, e.g. asystem administrator of the infrastructure of FIG. 4.

In addition to the information that the device in question is alive andconnected, the heartbeat sender 810 may be configured to transmit atleast some monitoring data, as well, which if received at the coremonitor service 148 from another monitor service, may be used to updatethe system landscape database 806. The heartbeat settings may be used todefine which such monitor data should be sent, along with the heartbeatmessages. In so doing, an amount of network traffic, power and otherresources may be conserved. Moreover, by receiving monitor data in theheartbeat messages, relatively-higher tier monitor services may avoidperforming at least some polling of lower-tier services, since theupper-tier services may already have the desired monitor data. Thedevice on which the core monitor service 148 is deployed may include theadditional monitor data along with heartbeat messages by executingqueries on the monitoring data storage, or by reading system adaptors134 (see FIGS. 6 and 9-11).

Heartbeat messages do not have to be sent over reliable communicationchannels, to the extent that the ping requestor 808 may, in response toan expected heartbeat message that does not come through, send anadditional request, e.g., if two consecutive pings are missing.Therefore, even if the communication channels are unreliable, andheartbeat messages are lost, the core monitor service 148 may continueto function. Accordingly, protocols such as, for example, thelightweight and connection-less User Datagram Protocol (UDP) may beused.

An algorithm consistent with the above explanation of the heartbeattransmitter 810 is provided below in the context of Code Section 3:

Code Section 3 Read heartbeat settings If time interval has changed then  Update timer component Get all data that should be included in theheartbeat message Send heartbeat message to parent with all queried dataSleep according to heartbeat settings

The ping requestor 808 may be understood as an addition to the heartbeattransmitter 810. For example, as referenced above, in the event of someconsecutively lost heartbeat messages, the ping requestor 808 may buildup a reliable connection to make sure that the ping is received andprocessed. Further, if a child device does not have a (functional)heartbeat transmitter 810, then the parent monitor's ping requestor 808may replace the heartbeat transmitter 810 completely. As a result, thechild system does not have to have a heartbeat transmitter installed, sofewer hardware capabilities may be used.

The core monitor service 148 also includes an update notificationtransmitter 812, which may be configured to provide services withupdates about the system landscape, such as, for example, changes inmonitor data, or registration of new devices, as may be determined,e.g., from the system landscape database 806. The update notificationtransmitter 812 thus may emit notification messages to all registeredrecipients, as stored in a recipient registry 814.

Services registered with the update notification transmitter 812 mayprecisely specify desired data, so as to obtain only the desired data(and minimize other transmissions). Constraints for what (types of)monitor data updates are transmitted may be based, for example, on thefollowing properties: a name of the data-providing service, or deviceand name of the data-field (e.g., alive-status, CPU usage, RAM size, orconnectivity values. Accordingly, subscription rules for receiving theupdates may be stored with the following information: an identifier ofthe recipient system, and a constraining rule (e.g., a source-systemidentifier and/or a data-field name). In some implementations, the tworestraining conditions may be connected with an AND, so that, forexample, both the name of the system AND of the data field must matchfor an update to be sent. In other implementations, an OR rule may berealized by defining more than one subscription rule.

An algorithm consistent with the above explanation of the updatenotification transmitter 812 is provided below in the context of CodeSection 4:

Code Section 4 Query recipient database: get all recipients that areregistered for this   service or device and data field For all foundrecipients do   Send update trigger message

FIG. 9 is a block diagram illustrating a system adaptor manager 902 foruse with the modular monitor service 600 of FIG. 6 and/or theimplementation of the core monitor service 148 illustrated in FIG. 8.Specifically, the system adaptor manager 902 may be used to manage thesystem adaptor(s) 134. As referenced above, the system adaptors 134 maybe configured to provide connections between the core monitor service148 and the various services and devices (e.g., the service 122 and/orthe device 108) that are supplying monitor data. It should be understoodthat the services, devices, and, therefore, monitor data may vary quitedramatically, due to the potential for heterogeneity in the systemlandscape. Accordingly, the system adaptors 134 may implement a commoninterface for communicating with the core monitor service 148, whileimplementing whatever other interfaces are necessary for monitoring(and, potentially, controlling) the various heterogeneous servicesand/or devices that may be present, so that the core monitor service 148need be aware of only this common interface in order to communicate witha large number of types of the system adaptors 134 (and, thereby, alarge number of types of services and devices).

Since the core monitor service 148 may be capable of communicating witha large number of the system adaptors 134 (using just the commoninterface), the core monitor service 148 either does not or cannotdetermine which of the system adaptors 134 is appropriate for a giventask. Rather, a system adaptor manager 902 is used in making such adetermination of a particular/correct one of the system adaptors 134 fora given task or setting. As such, the system adaptor manager 902represents an example of the module manager(s) 150, and provides anabstraction layer between the core monitor service 148 and the systemadaptor(s) 134. Accordingly, the core monitor service 148 may berelieved of the duty of tracking, selecting, or otherwise managing thevarious instances or possibilities of the system adaptors 134, much lessof the services or devices themselves.

As referenced above, the system adaptor(s) 134 may include, for example,a service adaptor and/or a device adaptor (see, e.g., FIG. 10), so thatcommunication between the core monitor service 148 (or other monitorservice modules 150) and a given service (e.g., the service 122) ordevice (e.g., the device 108) may be executed, and corresponding monitordata may be obtained. For example, the system adaptors 134 may beconsidered to be a part of the modular monitor service 600 that providesan interface to the environment (e.g., to the service 122 and/or thedevice 108). In the case of the device 108, a given one of the systemadaptors 134 may determine, for example, a CPU utilization, memoryusage, or memory size of the device. In the case of the service 122, agiven one of the system adaptors 134 may determine, for example, asoftware version or software vendor associated with the service 122.

Accordingly, it should be understood that there may be no definedstandard interface to the environment (e.g., to variousservices/devices), since each such service and device may have its ownspecific interface(s). Rather, the system adaptors 134 may be designedand implemented to fit to the monitored system(s) in question (e.g., thesystem 100). As such, the monitoring service(s) 132 a-132 d may readinformation about devices and services, whose different interfaces arehidden to the core monitor service 148 by the system adaptors 134 andthe system adaptor manager 902, so that the latter components provide anabstraction layer for use of the core monitor service 148.

The various types and instances of system adaptors 134 may be stored (orreferenced) in an adaptor registry 904, so that the system adaptormanager 902 may determine (e.g., based on a request of the core monitorservice 148, or based on a design choice of an administrator) whichsystem adaptor 134 to use in a given situation.

The system adaptor manager 902 may thus be configured to load and managea variety of system adaptors 134 that implement a common interface. Onstart-up, the system adaptors 134 may register at the adaptor manager902. The system adaptor manager 902 may execute a maintenance functionof all registered adaptors 134, where a maintenance function of thesystem adaptor 134 may implement internal management activity, inaddition to reading and returning monitor data (e.g., information aboutcurrently-running services, device-specific information, or sensor datacollected by the device on which the modular monitor service 600 isrunning).

In the example of FIG. 9, the system adaptors 134 include a basicinformation adaptor 906 and an OSGi adaptor 908. The basic informationadaptor 906 refers generally to service and/or device information thatmay be collected and used, e.g., in the system 100, such as the many andvarious examples of device metadata 130 provided above. The OSGi adaptor908 generally refers to the fact that the system adaptors 134 maysupport such standardized protocols as OSGi to get information aboutdevices that do not have one of the monitor services 132 a-132 dinstalled. Other examples for such protocol standards include the JavaAPI platform JSR232 (which includes OSGi), as well as Java APIs forBluetooth, JSR82.

FIG. 10 is a block diagram of an example implementation of the systemadaptors of FIGS. 1, 6, and 9. In the example of FIG. 10, an upper-tier(e.g., global or local layer) device 144, 146 is shown, which mayinclude, for example, a personal computer or server computer. Thedevice(s) 144, 146 include a core monitor service 148 a and/or 148 b,along with two system adaptors: a service adaptor 1002 (for interfacingwith a plurality of services 1004) and a device adaptor 1006 (forinterfacing with a plurality of instances/types of device hardware1008). As shown, the core monitor service 148 a, 148 b also maycommunicate with pre-registered devices 1010, which may be configured tointerface directly with the core monitor service 148.

Further in FIG. 10, a lower-tier (e.g., group leader or edge) device108, 110, 112, and/or 114 may represent a relatively more resource-poordevice, and may include the core monitor service(s) 148 c, 148 d.Similarly to the devices 144, 146, the devices 108, 110, 112, 114include a service adaptor 1012 (for interfacing with a plurality ofservices 1014) and a device adaptor 1016 (for interfacing with aplurality of instances/types of device hardware 1018). The devices 108,110, 112, 114 also include a separate device adaptor(s) 1020 that may beused to communicate with devices, e.g., a device 1024, that implementssuch standards 1022. For example, the device 1024 may represent a sensormote or cell phone that is running the management standard 1022 (e.g.,OSGi), so that the core monitor service 148 may communicate therewithusing the standard 1022.

FIG. 11 is a block diagram of another example implementation of thesystem adaptors of FIGS. 1, 6, and 9. In the example of FIG. 11, thesystem adaptor(s) 134 is illustrated as communicating with the coremonitor service 148. As described above, the system adaptor(s) 134 maycommunicate with the core monitor service 148 using an API 1102 of thecore monitor service 148 that is common to all of the system adaptor(s)134. The system adaptor(s) 134 also communicate with a service and/ordevice 1104 using an API 1106, which is specific to the service/device1104 and to the specific, associated instance of the system adaptor 134in FIG. 11.

In FIG. 11, the system adaptor 134 includes a notification system 1108that is configured to receive notifications from the core monitorservice 148 (e.g., from the update notification transmitter 812 of FIG.8). For example, as explained above in the context of FIG. 8, the coremonitor service 148 may send updates regarding changes in monitor data,or registration of new services or new devices. The notification system1108 (which may thus be understood to be included in the recipientregistry 814) may subscribe to particular notifications, or types ofnotifications, and so may receive notifications on a periodic orscheduled interval.

The notification system 1008 also may receive notifications from otherservices, such as, for example, a business logic rule engine service1110 (which implement business logic and may trigger reactions tocertain real-world events), or a logger or watchdog service (not shownin FIG. 11). The notifications may be forwarded or handled, depending onthe implementation of the system adaptor 134, and the system adaptor 134defines and implements an appropriate reaction to each possiblenotification.

The system adaptor 134 also includes a system reader 1112 that isconfigured to read monitor data from the service/device 1104, such as,for example, CPU utilization, battery lifetime, or status of the service(e.g., whether a service is running, or stopped). The system reader 1112may then provide the monitor data to the core monitor service 148 thatis polling the system adaptor 134.

in these and other implementations, the system reader 1112 may providethe monitor data to a heartbeat transmitter 1114. The heartbeattransmitter 1114, generally speaking, is configured to periodically senda life-signal to the core monitor service 148. As just referenced, andas referenced above with respect to FIG. 8, the heartbeat transmitter1014 also may receive and transmit monitor data from the service/device1104 (e.g., status values), which allows for a reduction in messagingoverhead. As described with respect to FIG. 8, heartbeat settings 1116may include parameters associated with the heartbeat transmitter 1114,such as, for example, a time interval between heartbeat messages.

Finally in FIG. 11, an initializer 1118 is configured to set up theheartbeat settings 1116, and register the monitor data at the monitordata storage (e.g., the system landscape database 806 of FIG. 8). Theinitializer 1118 also may be configured to register with the recipientregistry 814 for update notification messages at the update notificationtransmitter 812.

In the examples described herein, processing threads may be used forvarious tasks, including monitor service maintenance threads, or adaptorthreads. Such threads (for, e.g., context switching, thread scheduling,or inter-thread communication) may be created and managed, as needed.The monitor service thread may be used to keep monitor data, as storedin system landscape databases 806 and/or the global/local monitor data136/138, up-to-date, and may further be used to manage a status oflower-tier services and devices.

System adaptor threads may be implemented separately from the monitorservice maintenance thread, so that system adaptors 134 do not block themonitor service maintenance thread by performing complex ortime-intensive tasks. The system adaptors 134 may run as separatethreads, or may be executed by a thread of an associated monitormaintenance service. In the latter case, the monitor service maintenancethread may be blocked for the time of executing a maintenance functionof the system adaptors 134. The system adaptors 134, which may be calledby the monitor service, still can create temporary threads that dotime-consuming work in the background, so the monitor service thread isnot blocked.

System adaptors that use their own threads may generally be morepowerful. Also, such system adaptors do not block the monitor service,and so may perform time-consuming tasks, and/or wait for I/O interrupts.Additionally, such system adaptors have more freedom in deciding when tobe activated. Thus, such system adaptors are not dependent on calls bythe monitor service at an undefined point in time. Timers can be used toactively send heartbeats messages and to update landscape values.

Nonetheless, for limited devices, it may be more appropriate toimplement the system adaptors as passive components that use the monitorservice thread. In such cases, an overhead of creating and managingthreads may be avoided, at a cost of blocking the monitor service whileexecuting the system adaptor in question.

FIG. 12 is a block diagram of an example implementation of thecommunication adaptor 602 of the modular monitor service 600 of FIG. 6.As shown, a communication adaptor manager 802 a, 802 b may act as thecommunication abstraction layer of FIG. 8 that communicates with thecore monitor service 148. The communication adaptor manager 802 a, 802b, analogously to the system adaptor manager 902, manages andcommunicates with a communication adaptor 1202 for devices (so as tocommunicate with device(s) 1204), as well as with a communicationadaptor 1206 (so as to communicate with the service(s) 1208). As shouldalso be understood from the above description of the system adaptormanager 902, the communication adaptor manager 802 a, 802 b(communication abstraction layer) may be configured to load/unload thecommunication adaptors 1202, 1206, and to register (or de-register) thecommunication adaptors 1202, 1206.

FIG. 13 is a block diagram of another example implementation of thecommunication adaptor(s) 602 of FIG. 6. In FIG. 13 (as in FIG. 12), thecommunication adaptor manager (abstraction layer) 802 a, 802 b maysupport both local method calls and network communication. Furthermore,the communication adaptor manager (abstraction layer) 802 a, 802 b mayoperate to make communication protocols and network devices opaque tothe core monitor service 148.

For example, message handling and socket communication may be used fornetwork communication. Further, local communication may be realizedusing messages, APIs, sockets, pipes, and/or shared memory.

Thus, the communication adaptor manager 802 a, 802 b (communicationabstraction layer) hides currently-used protocols (e.g., TransferControl Protocol (TCP), Uniform Datagram Protocol (UDP), InternetProtocol (IP), Hyper Text Transfer Protocol (HTTP), or File TransferProtocol (FTP), which may work on different ISO/OSI layers, and/or whichmay be combined. The communication adaptor manager 802 a, 802 b(communication abstraction layer) also may hide network devices 1204(e.g., Bluetooth, modem, or WiFi devices). The communication adaptormanager 802 a, 802 b (communication abstraction layer) also may hidecertain communication concepts (e.g., message passing, sockets, sharedmemory, or API calls).

In other words, as already described with respect to the system adaptor134, the communication adaptor manager 802 a, 802 b may load or unload,for example, a TCP adaptor 1302, a UDP adaptor 1304, or an API callAdaptor 1306, which may each present a common interface to the coremonitor service 148. Thus, by making communication opaque for the coremonitor service 148 and other services, the example of FIGS. 12 and 13may allow avoidance of dealing with protocols, network devices, sequencenumbers, or transmission errors.

In FIG. 13, each of the adaptors 1302-1304 is identified as beingassociated with either network (1302, 1304) or local (1306)communication. Further, each of the adaptors 1302-1304 is identified asbeing associated with either reliable (1302, 1306) or unreliable (1306)communication. Each of the adaptors 1302-1306 also may be associatedwith a unique identifier (Adaptor ID), for use by the communicationadaptor manager 802 a, 802 b in selecting or loading the respectiveadaptor.

In general, unreliable data transfer may be much simpler and thereforeless resource consuming than reliable transfer. Therefore, unreliabledata transfer may be preferred, where possible. Some functionality,however, such as pinging a system, may require reliable data transfer(and corresponding communication adaptor).

So, in general, it should be understood from the example of FIG. 8 thatthe core monitor service 148 may send and receive different types ofmessages, and the communication adaptor manager 802 a, 802 b may be usedto select a corresponding, appropriate communication adaptor to executethe sending or receiving. For example, the core monitor service 148 mayneed to send a message over a network, using a lightweight andunreliable transport protocol. In this example, the communicationadaptor manager 802 b may locate the UDP adaptor 1304, among all loadedadaptors, which implements an unreliable network communication. Thecommunication adaptor manager 802 b then forwards the message to the UDPadaptor 1304, which performs the actual communication.

FIG. 14 is a block diagram of an example implementation of thepreprocessor module 606 of FIG. 6. For example, the preprocessor module606 may be used by one or more of the various monitor services 132 b-132d to process monitor data locally before forwarding the processedmonitor data to the next higher tier of the architecture of the system100 of FIG. 1.

In FIG. 14, a preprocessor manager 1402 is configured to operatesimilarly or analogously to the adaptor managers 802 a/802 b and 902,described above. For example, the preprocessor manager 1402 mayinterface with a preprocessor registry 1404 to determine an appropriateone of the possible preprocessor modules 606, for use with the coremonitor service 148. As shown, the preprocessor manager 1402 may beconfigured to receive incoming monitor data, such as from a localservice or device, and perhaps by way of the core monitor service 148and appropriate system adaptor 902 and/or communication adaptor 802 b.After preprocessing by the preprocessor module(s) 606, the preprocessormanager 1402 may output the preprocessed monitor data, e.g., back to thecore monitor service 148 for transmission to the next-higher tier of thesystem monitor architecture.

For example, the preprocessor module(s) 606 may include a filter 1406,an aggregator 1408, and an update notification transmitter 1410. Forexample, the filter 1406 may be configured to remove certain types ofmonitor data, or certain amounts. The aggregator 1408 may be configuredto combine received messages for transmission of a combined message. Forexample, the group leader monitor service 132 c may receive a messagefrom each edge device 110-114 for aggregation thereof, or may receive aseries of message from a single edge device (e.g., the edge device 110).

The update notification transmitter 1410, as described above, may beconfigured to provide updates, similarly to the update notificationtransmitter 812. In the example of FIG. 14, the update notificationtransmitter 1410 communicates updates to a GUI 1412, for viewing, e.g.,by a system administrator. Of course, the example of the GUI 1412 may bemost appropriate at higher-level tiers of the monitoring architecture.Further, in addition to aggregation and filtering, logging, computationof statistics, and other data preprocessors may be used for monitoringdata.

For example, the system adaptor 134 may deliver the CPU utilizationevery second, with a requirement that the average utilization over thelast two minutes be determined. To support scalability, the monitoreddata values may be preprocessed near to the measuring system adaptor. Inthis way, communication resources are conserved, since the need to sendeach data value (once a second) to the upper tier(s) may be avoided.Instead, e.g., on demand, only the aggregated value may be sent.

In operation, different ones of the preprocessor modules may register atthe core monitor service 148. As monitor data (e.g., status values) comein, each of the registered preprocessors is executed. For example, afirst preprocessing module may receive the raw monitor data as aparameter(s), and may return a preprocessed data set. Subsequently, thenext preprocessor is started, and received the preprocessed output datafrom the first preprocessor. Accordingly, each preprocessor may beexecuted, working on the output data of its predecessor.

In such examples, when using such a sequential execution of modules(e.g., plug-ins), it may be necessary to order execution of the plug-insappropriately. For example, two modules may register with the coremonitor service 148 and/or the preprocessor manager 1402. In thisexample, the first module may delete all data of a specific service ordevice, while the second module may compute the average CPU utilizationover all monitored devices. Clearly, the result is different if theorder of the two modules changes, because then all monitored servicesand devices are taken into account, including the specific service ordevice to be deleted.

Accordingly, the preprocessor manager 1402 may, e.g., duringregistration, set the appropriate execution order. To the extent that anumber and type of preprocessor modules 606 may be unknown atdesign-time, it may be difficult to assign an absolute execution order,particularly when the preprocessor modules may be loaded dynamically atruntime. Consequently, one option is to create groups of thepreprocessor modules 606, so as to order the preprocessor modules 606according to group. Each preprocessor module 606 may be associated witha group identifier, so as to be put into the correct group duringregistration. Then, the groups may be executed in order on agroup-level, if not at the level of individual preprocessor modules.Groups may be ordered based on, for example, a priority and/or type ofpre-processing performed. For example, a first group may includepreprocessor modules that must work on raw data, while a second groupmay work on already-preprocessed data, and a third group may processfinal data. Thus, a modular or plug-in concept for the preprocessingmodules 606 (e.g., 1406-1410) may increase a scalability of the system100 of FIG. 1, and may address resource-constraint issues. For example,scalability may be increased by relieving the global monitor service 132a and the local monitor service 132 b from some or all preprocessingtasks. Furthermore, the modular architecture allows the monitor service132 a-132 b configurable to the needs and capabilities of each device.

Other types of monitor service modules 150 may be implemented. Forexample, as shown in FIG. 6, a data storage module 604 may be used. Forexample, depending on capabilities of a device on which the globalmonitor service 132 a and the local monitor service 132 b are installed,a different technology for storing monitor data in the global monitordata 138 may be chosen than is chosen for storing monitor data in thelocal monitor data 136, e.g., either may store data in one or more of adatabase, a text file, an in memory data-structure, or virtually anyother kind of data storage. Use of the data storage module 604 may makesuch differences opaque to the monitoring service in question, using thevarious techniques described above with respect to FIGS. 6-14. Forexample, the monitor data storage may be encapsulated by a well-definedinterface, and the interface may serve as an abstraction layer from theactual data storage system.

FIG. 15 is a block diagram of a system 1500 illustrating a registrationprotocol for use with the system 100 of FIG. 1. In FIG. 15, a groupleader device 1502, which may be a portable device (e.g., a PDA orlaptop), enters into an area of a group leader device 1504. As shown,the group leader device 1504 is a group leader of a plurality of edgedevices 1506 a, 1506 b, 1506 c of a sensor network. Thus, for example,the group leader device 1504 and the edge devices 1506 a, 1506 b, 1506 cmay be involved in any number of sensor network applications, including,for example, inventory management or hazardous material tracking.

Accordingly, for example, the group leader device 1504 (which may be,for example, the same as the edge devices 1506 a, 1506 b, 1506 c, orwhich may be a WiFi access point or a base station, as referenced above)may be in the process of collecting information (i.e., monitor data)associated with inventory in a warehouse. For example, such monitor datamay include a type and quantity of stocked goods for sale, and/orcurrent temperature information in a vicinity of the stocked goods(e.g., to detect possible spoilage of food products). Thus, the groupleader device 1502 may enter the area of the group leader device 1504,such as when an employee enters the area with a PDA or other computingdevice, and wishes to obtain desired monitor data.

In the above example, and similar examples, the group leader device 1502may wish to collect the monitor data for local use by the employee,and/or may itself collect/transmit monitor data to a global monitorservice 1508. In the latter case, for example, the group leader device1502 may have certain computing resources or capabilities not available(or, at least, not currently available) in the group leader device 1504.It should be understood that, in the example of FIG. 15, the groupleader device 1502 may actually be currently acting as a group leader toa plurality of edge devices (not shown in FIG. 15), or may be referredto as a group leader device in the sense that sufficient computingresources are present to act at the group leader tier of theinfrastructure described herein (e.g., to split messages fordistribution to edge devices, or to filter/aggregate messages from theedge devices for subsequent transmission). In still other examples, itmay be the case that the group leader device 1504 has failed, or isabout to fail (e.g., due to low battery power), or is required tore-locate, so that the group leader device 1502 is being re-located forthe purpose of assuming the duties of the group leader device 1504.

In the example of FIG. 15, the global monitor service 1508 includesglobal monitor data 1510, and operates on a device 1512 (which mayinclude, as described herein, a PC or similarly-powerful computer). Theglobal monitor data 1510, as already described, may include globallandscape data related to the system 1500 as a whole, including otherelements not shown in FIG. 15. For example, the global monitor data 1510may include device metadata describing the group leader 1504 and theedge devices 1506 a, 1506 b, 1506 c (including, for example, both staticand dynamic device capabilities).

Moreover, the global monitor service 1508 may include device metadatarelated to the group leader device 1502. For example, the group leaderdevice 1502 may previously have been registered with the global monitorservice 1508 as part of a separate network(s) (not shown in FIG. 15). Asthe employee operating the group leader device 1502 re-locates from theseparate network to the area of the devices shown in FIG. 15, the groupleader device 1502 may disconnect as part of the separate network (andbe marked as such within the global monitor data 1510, as alreadydescribed), although information regarding the group leader device maybe maintained in the global monitor data 1510 for some period of time.

The system 1500 further includes a local monitor service 1514, withlocal monitor data 1516 and running on a device 1518. The device 1518may include, for example, a laptop computer or a Stargate computer, asdescribed. Further, the system 1500 may include a local monitor service1520, with local monitor data 1522 and running on a device 1524.

In the example of FIG. 15, then, the group leader device 1502 may needto register with the global monitor service 1508 in order, for example,to establish a connection 1526 with the group leader 1504. For example,it may be the case that the group leader device 1502 and the groupleader device 1504 may have overlapping abilities to communicate withone another; e.g., both may have Bluetooth capabilities. Even so, thegroup leader device 1502 may be unaware that the group leader device1504 has Bluetooth capabilities, and, moreover, the group leader device1502 may have no local communication service (e.g., adaptor/module) thatis compatible both with Bluetooth and with whatever service(s) are beingrun on the group leader device 1504 (e.g., the temperature reportingservice referenced above).

In contrast, however, the global monitor service 1508 may be well awareof all such information, as stored within the global monitor data 1510(e.g., appropriate service metadata and/or device metadata). Of course,information regarding the group leader device 1504 also may be stored inthe local monitor data 1516, as should be understood from thedescription above. Thus, the global monitor service 1508 is (indirectly)capable of establishing the connection 1526, since, for example, theglobal monitor service 1508 may be able to determine whichcommunications services (adaptors/modules) are needed, and may thendownload and/or inject such a service(s) onto the group leader device1502. The global monitor service 1510 also may communicate with thegroup leader device 1504, in order to ensure (by injecting, ifnecessary) that the group leader device 1504 not only has Bluetooth (orother communication protocols/standards), but also has a local servicethat is compatible both with Bluetooth and with a corresponding serviceon the group leader device 1502.

In this way, the connection 1526 may be established. In analogoussituations, the group leader 1502 may otherwise communicate with otherdevices/services of the system 1500. Thus, registration of the groupleader device 1502 within the system 1500 may provide a number ofadvantages, for example, to a user of the group leader device 1502.

Such registration, however, may be associated with a number ofdifficulties. For example, such registration may represent a securityissue, since unregistered and possibly malicious devices should notgenerally be monitored and integrated into the system 1500. Also,frequent exchanges of registration messages may consume valuablebandwidth, battery power, or other communications resources. If devicesare not registered, though, then such devices may be un-identified andun-accessed by the rest of the system 1500.

Thus, the following description, along with FIGS. 15-17, provideexamples of how the group leader device 1502 may register with theglobal monitor service 1508. Of course, it should be understood thatthis is but one example, and many other examples may be used toimplement the described registration protocol, or variations of thedescribed registration protocol, as would be apparent.

In FIG. 15, then, it is assumed for the example that the group leaderdevice 1502 has a monitor service installed thereon (although not shownin FIG. 15). Such a monitor service may include the variousimplementations described herein, including the modular monitor serviceof FIG. 6, or may include a non-modular, e.g., integrated, monitorservice. The group leader device 1502 and its installed monitor servicethus attempt to join the network(s) of the system 1500, includingregistering at the global monitor service 1508.

The group leader device 1502 includes a registration system 1528 andregistration data 1530. The registration system 1528 is configured toexchange registration messages 1532, 1534, 1536, and 1538 with one ormore of the local monitor services 1514, 1520 (and/or with the globalmonitor service 1508). The registration data includes information aboutthe connecting monitor service of the group leader device 1502, such as,for example, metadata related to a current status of the group leaderdevice 1502, or device metadata related to the group leader device 1502.The registration data also may include initial sensor status/valuesinformation (e.g., to avoid overhead caused by an initial polling forsuch values, which would take place right after registration, since datais outdated or not existent. In cases where an excessive amount ofvalues would be included in the registration data, then at least staticdata values may be sent).

Although registration data 1530 is illustrated conceptually as/in amemory in FIG. 15, it should be understood that the registration data1530 may simply represent values collected by the group leader device1502 (e.g., by the registration system 1528 and/or by a monitor serviceof the group leader device), either during or before registration takesplace. Of course, the group leader device 1502 may have a memory in someexample implementations. Moreover, in cases where a local monitorservice attempts to register with a new network, then it should beunderstood from the above description that a local memory (e.g., thelocal monitor data 1516, 1522) may be used. More generally, it should beunderstood that the registration system 1528 and registration data 1530,or variations thereof, may be implemented within other ones of thedevices and monitor services of FIG. 15.

The described registration protocol may be implemented as a simple,e.g., connectionless, protocol, that is robust. Additionally, theregistration protocol is configured to support both active registration(e.g., initiated by a connecting device) and passive registration (e.g.,initiated by a connected network device). Consequently, as described,the registration process may be started by either device.

In FIG. 15, then, the group leader device 1502, as anunregistered-but-now registering device sends out a solicitation message1532. The solicitation message 1532, which may be sent as a broadcastmessage, may contain a request for, or identification of, a specifictype of same or next-higher level monitor service, and the request maybe based in part on device capabilities of the connecting device. Forexample, if the (registering) group leader device 1502 has certaincapabilities (e.g., is a mobile phone), then it may try to locate othergroup leader devices (e.g., the group leader device 1504, i.e., amonitor service thereof) and/or local monitor services (e.g., 1514,1520), rather than the global monitor service 1508.

If no suitable instance of the preferred monitor service type is found,then the registration system 1528 may re-send the solicitation message1532 with an identification of a next-higher level (going up from lowerto higher level monitor services). Further, if the solicitation message1532 is lost, then the registration system 1528 may simply send anothersolicitation message, e.g., after a timeout. Solicitation messages thatare received twice are not an issue, since this is the initial step ofthe protocol. Therefore, a lightweight and connectionless transportationprotocol, e.g., UDP, may be sufficient.

Accordingly, the solicitation message 1532 may be sent out periodicallyif no answer is received. After some repetitions, the group leader(i.e., registering, or connecting) device assumes that there is nomonitor service, and stops sending messages for at least a specifiedtime interval, which saves power and computation time.

Meanwhile, already-connected and registered services of the system 1500(e.g., the local monitor service 1520) may send out an advertisementmessage 1534. The advertisement message 1534 may be sent, for example,either in response to a timer or to the solicitation message 1532. Theadvertisement message 1534 may include an identification of a type ofmonitor service that is sending the advertisement message 1534 (e.g.,the local monitor service 1520 in the example of FIG. 15). By receipt ofthe advertisement message 1534, other monitor services in the networkbecome aware that there is a monitor service of a designated type thatis currently accepting child monitor services, and become aware of howto communicate with this available monitor service. The advertisementmessage 1534 may be sent as a broadcast message, and may be sent by anyor all of the devices described herein (except, generally, the variousedge devices, to the extent that the edge devices do not typically haveany child monitor services connected thereto).

The advertisement message 1534 provides a fail-safe mechanism in casethe solicitation message 1534 is lost, and also may act as an initiatorof the registration process, e.g., for devices that do not sendsolicitation messages. For example, the group leader device 1502 may, asreferenced above, stop sending solicitations after a specified timeperiod, or if devices cannot detect network changes. Using theadvertisement message 1530, such devices may be “reactivated.” Also,lost advertisement message are not disruptive, in that they may beresent from time to time.

A connecting/registering device, such as the group leader device 1502,may respond to the advertisement message 1534 once by sending aregistration message 1536. As referenced above, the registration message1536 may contain, for example, information about monitored data,landscape metadata, device metadata, and/or actual monitored (e.g.,sensor) values.

Once the registration message 1536 is successfully received at thesender of the advertisement message 1534 (i.e., the local monitorservice 1520), registration data may be saved in all devices on the pathfrom the receiving, parent monitor to the global monitor service 1508(e.g., in the example of FIG. 15, may be stored at the device 1524 and1512, as well as at any intervening devices). In other words, theregistration message 1536 is forwarded to the upper layer monitorservices.

Outdated data within the memories (e.g., 1510, 1522) of the upper layermonitor service may be marked as “in doubt,” and/or may be deleted toavoid inconsistencies. For example, the global monitor data 1510 mayhave information from a previous registration event that the groupleader device 1502 is currently connected to another network (not shownin FIG. 15). As the group leader device 1502 is moved away from devicesof the former network, however, the former connection is lost, so thatdata within the global monitor data 1510 becomes outdated. Once thegroup leader device 1502 registers again through the local monitorservice 1520, as shown in FIG. 15, then a current registration status,location, and other information/data within the global monitor data 1510may be updated accordingly.

The registration system 1536 may ensure that duplicates of theregistration message 1536 are not problematic, by allowing only onemessage-triggered registration message 1536 during a registrationprocess. That is, the registration system 1536 may be configured toignore any additional advertisement message(s) 1534, once theregistration message 1536 is sent.

The registration message 1536 then obtains a confirmation message 1538to ensure that the registration was processed successfully. If noconfirmation has arrived after a pre-determined time, the registrationmessage 1536 may be resent. Duplicate registration messages are noproblem in such implementations, because one registration may be allowedto override another registration without causing any harm. Additionally,or alternatively, duplicated registration messages may simply be ignoredif the relevant service or device is already registered.

The confirmation message 1538 may be sent by the managing monitorservice (e.g., the local monitor service 1520). The registration processfinishes when the registering device (the group leader device 1502)receives the confirmation message 1538 (if the confirmation message 1538is not received, e.g., is lost, then the group leader device 1502 maysimply re-send the registration message 1536). The now-registeredmonitor service of the group leader device 1502 may then begin itsassigned monitoring tasks. Thus, the registration protocol of FIG. 15allows for connectionless and unreliable data transfer, so that simpleand robust protocols, e.g., UDP, may be used.

FIG. 16 is a sequence diagram illustrating an example implementation ofthe registration protocol of FIG. 15. In the example of FIG. 16, variousexceptions occur, in order to illustrate the robust nature of theprotocol.

In particular, a solicitation message is sent from the group leaderdevice 1502 (e.g., from a group leader monitor service installedthereon) to the local monitor service 1520, but is not received (1602).That is, the solicitation message includes an identification that it isa local monitor service that is desired as a parent device, but no suchpotential parent device receives or responds to the message.

After a designated time, a second solicitation message(s) is/are sent(1604), which is received at both the local monitor service 1520 and theglobal monitor service 1508. As described above, the registration system1528 may determine that because the sending of the first solicitationmessage (1602) was unsuccessful, it may be necessary to send a secondsolicitation message.

In this case, both the local monitor service 1520 and the global monitorservice 1508 receive the solicitation message (1604). However, theglobal monitor service 1508 simply ignores (1606) the solicitation,since the solicitation specifies the local monitor service 1520.

Then, the local monitor service 1520 sends out an advertisement message(1608 a and 1608 b). The advertisement message may be sent (1608 a) inresponse to the sending of the solicitation message(s) (1604), or may besent based on a timer value. The sending of the additional advertisementmessage (1608 b) as part of a broadcast thus arrives at the globalmonitor service 1508, but is ignored (1610).

The group leader device 1502 then sends a registration message (1612),causing the local monitor service to register associated metadata(1614). At this point, although not shown, the registered metadata maybe forwarded to the global monitor service 1508 (e.g., using deltasynchronization). Then, a confirmation message may be sent, but, in theexample of FIG. 16, is not received at the registration system 1528(1616). Accordingly, the registration system 1528 of the group leaderdevice 1502 simply resends the registration message (1618), which isthen received again at the local monitor service 1520, and eitherre-registered (1620) or ignored. A confirmation message is sent again,and this time is received at the group leader device 1502 (1622), thusending the registration process.

FIG. 17 is a flowchart 1700 illustrating example operations of thesystem 1500 of FIG. 15. In the example of FIG. 17, a connecting monitorservice (e.g., a monitor service of the group leader device 1502, whichmay include or be associated with the registration system 1528)broadcasts a solicitation message (e.g., the solicitation message 1532),including an identification of a desired parent service from within thehierarchical monitor architecture of the system 1500 (1702).

If the solicitation message 1532 is not received at the parent service(e.g., at the local monitor service 1520) (1704), then the parentmonitor service may continue waiting for a pre-defined timer (1706).Thus, if the timer is reached, or if the solicitation message isreceived at the parent monitor service, then the parent monitor servicemay receive the resulting advertisement message, e.g., the advertisementmessage 1534 (1708). As should be understood, then, the advertisementmessage 1534 may be sent whether the solicitation message 1532 isreceived or not, thus increasing the likelihood ofconnection/registration of the connecting device.

If the advertisement message 1534 is not received at the connectingdevice (1710), then the connecting device may re-send the solicitationmessage 1532 (1712), perhaps identifying a next-higher level of thehierarchical monitor architecture as the desired parent service (e.g.,the global monitor service 1508 instead of the local monitor service1520, 1514). In this case, as long as a time-out is not reached (1714),then the process may continue until a registration and/or advertisementmessage(s) are exchanged. Otherwise, the process is stopped (1716). Inthis regard, it should be understood that the time-out condition mayrefer literally to a period of time that has passed, or may refer to thesending of a pre-defined number of (a certain type of) message(s).

It should be understood, of course, that the advertisement message maybe resent (1708), according to its associated timer (1706), even if theprocess was previously stopped or failed. Moreover, virtually any “stop”condition in FIG. 17, including the stop condition (1716), may betemporary, and the process may continue after some further-definedperiod is reached.

If the advertisement message is received (1710), then the connectingdevice may send a registration message, e.g., the registration message1536, to the parent monitor service identified in the advertisementmessage (1718). If the registration message is not received (1720), anda timer is not reached (1722), then the connecting device may re-sendthe registration message (1718). As described, the registration messagemay include monitor data, so that, if the registration message isreceived (1720), the registration message may be propagated up thehierarchy (1726), e.g., to the global monitor service 1508. In thiscase, the monitor data, including metadata about the connecting deviceand actual sensor values may be saved at some or all of the interveningdevices (1728), e.g., the local monitor service 1520. By propagating theregistration/monitor data in this way, the global monitor service 1508may keep track of the existence of the connecting service/device, andmay delete eventual left-over data marked as “in doubt” that mayotherwise cause inconsistencies (e.g., the same device registered indifferent networks simultaneously).

Then, the parent monitor service may send a confirmation message (1730),e.g., the confirmation message 1538. If the confirmation message is notreceived (1732), and a time-out has not been reached (1734), then theregistration message may be re-sent (1718), and the above-describedprocess may be repeated, in whole or in part. If the time-out isexceeded (1734), or if the confirmation message is received, then theregistration process ends, as well (1724).

The just-described registration protocol(s) may be implemented when theconnecting device (e.g., the group leader device 1502) already has amonitor service installed thereon. As described above with respect toFIG. 7B, however, if the connecting device does not have a monitorservice installed thereon, then a pre-registration process may beconducted in which, as described above, a boot-strapping technique maybe used in which the core monitor service 148 is installed, and then isused to execute the remaining registration processes of FIGS. 15-17.

As just described, a robust and reliable registration protocol of FIGS.15-17 allows for the use of unreliable/connectionless communicationsprotocols, while minimizing an amount of network bandwidth required forthe registration process. For example, network bandwidth may beconserved by stopping re-sending of one or more of the messages after acertain period of time. In this case(s), each time the registrationprotocol requires resending messages after timeouts, there is apossibility that either the connecting device or parent service may havelost a connection, and this possibility may lead to a “stuck” state forsome or all of the system 1500. To avoid this state, and as referencedabove, each re-sent message may be re-sent for a limited number of timesonly, and, if no successful registration is achieved the entireregistration process may restart.

It should be understood that the above description is merely intended toprovide examples of a hierarchical layering of a monitor architecture,and that greater or fewer layers of such a hierarchy may be used. Byimplementing such hierarchically-layered architectures, e.g., asdescribed in more detail above, various features and advantages may beobtained. For example, as referenced above, the system(s) describedherein 100 may easily be scaled up to include a large number of smartitem devices, while still being able to perform efficient monitoring ofservices and/or devices.

Implementations of the various techniques described herein may beimplemented in digital electronic circuitry, or in computer hardware,firmware, software, or in combinations of them. Implementations mayimplemented as a computer program product, i.e., a computer programtangibly embodied in an information carrier, e.g., in a machine-readablestorage device or in a propagated signal, for execution by, or tocontrol the operation of, data processing apparatus, e.g., aprogrammable processor, a computer, or multiple computers. A computerprogram, such as the computer program(s) described above, can be writtenin any form of programming language, including compiled or interpretedlanguages, and can be deployed in any form, including as a stand-aloneprogram or as a module, component, subroutine, or other unit suitablefor use in a computing environment. A computer program can be deployedto be executed on one computer or on multiple computers at one site ordistributed across multiple sites and interconnected by a communicationnetwork.

Method steps may be performed by one or more programmable processorsexecuting a computer program to perform functions by operating on inputdata and generating output. Method steps also may be performed by, andan apparatus may be implemented as, special purpose logic circuitry,e.g., an FPGA (field programmable gate array) or an ASIC(application-specific integrated circuit).

Processors suitable for the execution of a computer program include, byway of example, both general and special purpose microprocessors, andany one or more processors of any kind of digital computer. Generally, aprocessor will receive instructions and data from a read-only memory ora random access memory or both. Elements of a computer may include atleast one processor for executing instructions and one or more memorydevices for storing instructions and data. Generally, a computer alsomay include, or be operatively coupled to receive data from or transferdata to, or both, one or more mass storage devices for storing data,e.g., magnetic, magneto-optical disks, or optical disks. Informationcarriers suitable for embodying computer program instructions and datainclude all forms of non-volatile memory, including by way of examplesemiconductor memory devices, e.g., EPROM, EEPROM, and flash memorydevices; magnetic disks, e.g., internal hard disks or removable disks;magneto-optical disks; and CD-ROM and DVD-ROM disks. The processor andthe memory may be supplemented by, or incorporated in special purposelogic circuitry.

To provide for interaction with a user, implementations may beimplemented on a computer having a display device, e.g., a cathode raytube (CRT) or liquid crystal display (LCD) monitor, for displayinginformation to the user and a keyboard and a pointing device, e.g., amouse or a trackball, by which the user can provide input to thecomputer. Other kinds of devices can be used to provide for interactionwith a user as well; for example, feedback provided to the user can beany form of sensory feedback, e.g., visual feedback, auditory feedback,or tactile feedback; and input from the user can be received in anyform, including acoustic, speech, or tactile input.

Implementations may be implemented in a computing system that includes aback-end component, e.g., as a data server, or that includes amiddleware component, e.g., an application server, or that includes afront-end component, e.g., a client computer having a graphical userinterface or a Web browser through which a user can interact with animplementation, or any combination of such back-end, middleware, orfront-end components. Components may be interconnected by any form ormedium of digital data communication, e.g., a communication network.Examples of communication networks include a local area network (LAN)and a wide area network (WAN), e.g., the Internet.

While certain features of the described implementations have beenillustrated as described herein, many modifications, substitutions,changes and equivalents will now occur to those skilled in the art. Itis, therefore, to be understood that the appended claims are intended tocover all such modifications and changes as fall within the true spiritof the embodiments of the invention.

1. A method comprising: transmitting, from a registering monitor serviceat a first tier of a hierarchical, multi-tier monitoring architecturefor a plurality of separate device networks, each device networkincluding a plurality of wireless devices in wireless communicationswith one another and with a group leader device executing a group leadermonitor service at another level of the hierarchical, multi-tiermonitoring architecture, a broadcast solicitation message identifyingboth the registering monitor service and a registered monitor serviceassociated with a second tier of the hierarchical, multi-tier monitoringarchitecture, wherein the second tier is specified relative to aplurality of available tiers of the hierarchical, multi-tier monitoringarchitecture, wherein each group leader device is in communications witha local monitor device executing a local monitor service at anotherlevel of the hierarchical, multi-tier monitoring architecture and eachlocal monitor device is in communications with a global monitor deviceexecuting a global monitor service at another level of the hierarchical,multi-tier monitoring architecture; transmitting, from the registeredmonitor service, a broadcast advertisement message indicating anidentity and availability of the registered monitoring service forregistration, the advertisement message including an identification ofthe registered monitor service at the second tier, wherein theadvertising message is sent in response to the solicitation message orindependently thereof; transmitting, from the registering monitorservice and in response to the advertisement message, a registrationmessage including registration data associated with the registeringmonitor service; and registering the registering monitor service at thesecond tier within the hierarchical, multi-tier monitoring architecture,based on the registration data, including storing at least a portion ofthe registration data at each higher tier of the hierarchical,multi-tier monitoring architecture; and establishing a communicationslink between the registering monitor service and additional registeredmonitor services running on devices at the first tier and lower tiers,if any, based on the stored registration data.
 2. The method of claim 1comprising transmitting, from the registered monitor service, aconfirmation message confirming registration of the registering monitorservice.
 3. The method of claim 1 wherein transmitting the solicitationmessage comprises transmitting the solicitation message to the secondtier, after a previous solicitation message identifying an interveningtier from among the plurality of available tiers of the hierarchical,multi-tier monitoring architecture does not result in receiving theadvertisement message.
 4. The method of claim 1 wherein transmitting thesolicitation message comprises broadcasting the solicitation message ata pre-determined time interval.
 5. The method of claim 3 whereintransmitting the advertisement message comprises: ignoring the previoussolicitation message for failure to identify the second tier; andtransmitting the advertisement message based on the solicitation messageincluding its identification of the second tier.
 6. The method of claim1 wherein transmitting the advertisement message comprises transmittingthe advertisement message based on a pre-determined time interval. 7.The method of claim 1 wherein transmitting the registration messagecomprises: including, within the registration data, device metadatawithin the registration message and associated with a device on whichthe connecting service is deployed, and/or including, within theregistration data, service metadata within the registration message andassociated with a service deployed on the device.
 8. The method of claim1 wherein transmitting the registration message comprises including,within the registration data, sensor values obtained by a sensorassociated with the connecting service.
 9. The method of claim 1 whereintransmitting the registration message comprises: re-transmitting theregistration message until the confirmation message is received or untila time-out condition is reached.
 10. The method of claim 1 whereintransmitting the registration message comprises: discarding, at theregistering monitor services, a further advertisement message receivedafter the registration message is transmitted.
 11. The method of claim 1wherein transmitting the registration message comprises: storing theregistration data using at least one device associated with theregistered monitor service.
 12. The method of claim 1 comprising:deploying a core monitor service onto the registering monitor service;determining device metadata associated with a device on which theregistering monitor service is deployed; deploying at least one monitorservice module onto the device, based on the device metadata; andtransmitting the solicitation message, receiving the advertisementmessage, and/or transmitting the registration message, using the atleast one monitor service module.
 13. A system comprising: a registeringmonitor service at a first tier of a hierarchical, multi-tieredmonitoring architecture that is configured to obtain and report monitordata collected by a plurality of separate device networks, each devicenetwork including a plurality of wireless devices in wirelesscommunications with one another and with a group leader device executinga group leader monitor service at another level of the hierarchical,multi-tiered monitoring architecture, wherein each group leader deviceis in communications with a local monitor device executing a localmonitor service at another level of the hierarchical, multi-tieredmonitoring architecture and each local monitor device is incommunications with a global monitor device executing a global monitorservice at another level of the hierarchical, multi-tiered monitoringarchitecture, the registering monitor service comprising: a registrationsystem configured to broadcast a solicitation message from theregistering monitor service, the solicitation message specifying a tierfrom among a plurality of tiers of the hierarchical, multi-tieredmonitoring architecture that are potentially available for registration,a registered monitor service at a higher-level tier of the hierarchical,multi-tiered monitoring architecture, the registration system beingfurther configured to receive an advertisement message that is broadcastfrom the registered monitor service in response to the solicitationmessage or independently thereof, determine that the registered monitorservice is a member of the specified tier based on the advertisementmessage, and send a registration message to the registered monitorservice, the registration message including registration data associatedwith the registering monitor service, wherein at least a portion of theregistration data is stored at each higher tier of the hierarchical,multi-tier monitoring architecture, and wherein the monitor service isconfigured to establish a communications link between the registeringmonitor service and additional registered monitor services running ondevices at the first tier and lower tiers, if any, based on the storedregistration data.
 14. The system of claim 13 wherein the registrationsystem is configured to receive a confirmation message from theregistered monitor service, in response to the registration andconfirming that the monitor service is registered with the globalmonitor service.
 15. A method comprising: receiving a solicitationmessage broadcast by a registering monitor service at a registeredmonitor service of a hierarchical, multi-tiered monitor architecture fora plurality of separate device networks, each device network including aplurality of wireless devices in wireless communications with oneanother and with a group leader device executing a group leader monitorservice at another level of the hierarchical, multi-tiered monitorarchitecture, wherein each group leader device is in communications witha local monitor device executing a local monitor service at anotherlevel of the hierarchical, multi-tiered monitor architecture and eachlocal monitor device is in communications with a global monitor deviceexecuting a global monitor service at another level of the hierarchical,multi-tiered monitor architecture; determining that the registeringmonitor service is not registered through the registered monitor serviceas a member of the hierarchical, multi-tiered monitor architecture;determining an identification of a tier from among a plurality of tiersof the hierarchical, multi-tiered monitor architecture that arepotentially available for registration, the tier being specified in thesolicitation message, the registered monitor service being deployed onthe tier; broadcasting an advertisement message to the registeringmonitor service, in response to the solicitation message orindependently thereof, the advertisement specifying the registeredmonitor service as being deployed on the tier and available forregistration; receiving a registration message from the registeringmonitor service in response to the advertisement message, theregistration message including registration data associated with theregistering monitor service; registering the registering monitor servicewithin the hierarchical, multi-tiered monitor architecture, based on theregistration message, wherein at least a portion of the registrationdata is stored at each higher tier of the hierarchical, multi-tieredmonitor architecture; and establishing a communications link between theregistering monitor service and additional registered monitor servicesrunning on devices at the first tier and lower tiers, if any, based onthe stored registration data.
 16. The method of claim 15 comprisingsending a confirmation message to the registering monitor service. 17.The method of claim 15, comprising receiving a second solicitationmessage from a second monitor service at the registered monitor service,the second solicitation message identifying a different tier from amongthe plurality of tiers; and ignoring the solicitation message, based onthe identification of the different tier.